Association between calcium intake and risk of breast cancer: An updated systematic review and dose-response meta-analysis of cohort studies

BACKGROUND

Prospective cohort studies that dietary or total calcium intake was considered as the exposure variable and risk of BC as the main or second outcome were included in this systematic review.

METHODS

We searched the online databases of PubMed, Web of science, Scopus and, Google scholar for relevant studies published up to November 2021, using relevant keywords. Seven cohort studies including 1,579,904 participants, were eligible for the current meta-analysis.

RESULTS

Pooled effect size for the highest versus lowest category indicated that increasing dietary calcium intake was significantly associated with a reduced risk of BC (RR, 0.90; 95% CI: 0.81-1.00). However, total calcium intake revealed a non-significant inverse association (RR, 0.97; 95%CI, 0.91-1.03). Dose-response meta-analysis showed that every additional 350 mg per day dietary (RR, 0.94; 95% CI, 0.89-0.99) and total calcium intake (RR, 0.99; 95% CI, 0.97-1.00) was significantly associated with a lower risk of BC. Also, a significant decreasing trend for the risk of BC was observed after 500 mg/d of dietary calcium intake (P-nonlinearity = 0.05, n = 6.

CONCLUSION

Finally, our dose-response meta-analysis revealed a 6 and 1% lower risk of BC in each 350 mg per day increment in dietary and total calcium intake, respectively.

Dietary calcium intake and the risk of stroke: Meta-analysis of cohort studies

BACKGROUND AND AIMS

Prospective cohorts are inconsistent regarding the association between dietary calcium intake and the risk of stroke. The aim was to perform a meta-analysis to determine whether an association exists between them in cohort studies.

METHODS AND RESULTS

Relevant studies were identified by searching PubMed, EMBASE and Web of Science databases that published before December 2022. Prospective cohort studies that provided relative risk (RR) estimates with 95% confidence intervals (CIs) for the association were included. Study-specific risk estimates were combined by using a random effects model. Eighteen prospective studies, including 19,557 stroke cases among 882,181 participants, were pooled in the meta-analysis. We observed a nonlinear association between calcium intake and risk of stroke (P_nonlinearity < 0.003). Compared with the lowest value of zero assumed as the reference, the RRs (95% CI) of stroke across levels of calcium intake were 0.95 (0.92, 0.98) for 200 mg/day, 0.94 (0.90, 0.98) for 300 mg/day, 0.95 (0.90, 0.99) for 500 mg/day, 0.98 (0.93, 1.03) for 700 mg/day, and 1.04 (0.97, 1.11) for 1000 mg/day. The stratified analyses by geographic region showed nonlinear associations and indicated that the protective effect was observed in Asian countries (P_nonlinearity = 0.001) but not in non-Asian regions (P_nonlinearity = 0.047).

CONCLUSION

This meta-analysis suggests that dietary calcium intake might play an effective role in the prevention of stroke, especially in Asian countries. Future research among Asia population should attempt to establish whether this association is causal.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022357710.

Relationships between serum and dietary magnesium, calcium, and metabolic parameters in women with type 2 diabetes mellitus

BACKGROUND & AIMS

Magnesium and calcium are essential minerals in several enzymatic activities that modulate essential biological functions. Hypomagnesemia occurs in patients with type 2 diabetes mellitus (T2DM), especially those with poor metabolic control. Dietary magnesium and calcium intake play a protective role in the development of T2DM. This research aimed to investigate the association of dietary and serum magnesium and calcium with metabolic control parameters in diabetic women.

METHODS

This case-control study was conducted on 80 women, including 40 patients diagnosed with T2DM and 40 healthy controls aged 35-60 years. Some anthropometric measurements of the individuals were taken, and their body mass index was calculated. In addition, some biochemical parameters, serum magnesium, and calcium were analyzed. A validated 96-item quantitative food frequency questionnaire was used to obtain dietary magnesium and calcium intake data.

RESULTS

Serum magnesium levels were lower in subjects with diabetes than in controls, and there was a similar incidence of hypomagnesemia in T2DM patients and controls, but not statistically significant (p > 0.05). In T2DM patients, there was a statistically significant inverse association between HbA1c and serum magnesium (p < 0.05). Dietary magnesium intake was inversely associated with HOMA-IR scores (p < 0.05) but had a positive association with serum magnesium levels in patients with T2DM (p < 0.05). There were no significant differences in the calcium/magnesium ratio between T2DM patients and healthy controls (p > 0.05). In a multiple linear regression analysis, dietary magnesium intake and HbA1c were found to be significantly related to altered serum magnesium in T2DM patients.

CONCLUSION

The present findings suggest that lower serum magnesium levels were associated with higher HbA1c levels in subjects with T2DM. Increased dietary magnesium intake in T2DM may enhance HOMA-IR scores and serum magnesium levels.

Determinants of the attitudes of proinnovative dairy consumers and a model simulating consumer behavior regarding increasing calcium intake

OBJECTIVE

A study was carried out to identify characteristics of consumers of dairy products.

METHODS

Based on a questionnaire with 127 participants, aged 22 to 52, a simulation model was developed, taking into account factors influencing the development of health-seeking behavior.

RESULTS

A relationship was found between consumer proinnovative attitude, actual prohealth behavior, and characteristics of the consumer influencing the consumption of calcium. Prohealth behavior (knowledge and application of the principles of healthy eating) is mainly influenced by material situation, age, and gender of the consumer. It has been reported that only 25% of parents talk to their children about the principles of healthy eating. No relationship was found between prohealth and proinnovation behaviors and level of education, sports activity, or number of children in the family.

CONCLUSIONS

Among young people, as many as 39% do not follow the principles of healthy eating, and these are mainly women. Respondents' proinnovative attitudes and social status were conducive to increasing calcium intake and correlate with greater diversity in the consumption of dairy products. The Pearson correlation coefficient between body mass index and calcium intake was not significant (r = -0.03; P = 0.76).

Cow's milk allergy in children impacts parental or caregiver calcium intake

Food allergies have become a global epidemic, affecting more than 10% of the population and 8% of children worldwide. Eliminating or limiting a food group from the diet can adversely impact micronutrient consumption. Milk allergies can impact the amount of calcium consumed in the diet, serving as a barrier to meeting daily calcium needs. Previous research evaluates the nutritional impact food allergies may have on children diagnosed with food allergies; however, there is a marked gap in literature that investigates the impact that children's allergy may have on their parent or caregiver. We hypothesized that milk elimination in a child's diet resulting from a milk allergy is associated with inadequate calcium intake among parents. Study participants (n = 55) lived in the United States and included parents or caregivers of a child with a diagnosed milk allergy (experimental group) and parents of a child without a milk allergy (control group). Calcium intake was estimated by using the validated Calcium Assessment Tool. Results demonstrated that the experimental group consumed significantly less calcium (273 mg/d) than the control group (520 mg/d; P < .01). Notably, both groups consumed inadequate calcium relative to the calcium Recommended Dietary Allowance for adults of 1000 mg/d, although calcium supplementation was not assessed in this study. Key findings from this study indicate widespread inadequate dietary calcium intake and suggest a need for increased calcium consumption in this population.

Role of metabolic equivalent between calcium intake and vertebral fractures: a cross-sectional study of NHANES 2013-2014

BACKGROUND

This study was to analyze the association of calcium intake and metabolic equivalent (MET) with vertebral fractures, and to explore the role of MET between calcium intake and vertebral fractures.

METHOD

This cross-sectional study used data from the National Health and Nutrition Examination Surveys (NHANES) 2013-2014. The study involved individuals aged ≥ 50 years old with complete information on vertebral fracture, calcium intake, and physical activity. Vertebral fracture assessment is obtained using dual-energy x-ray absorptiometry to perform a lateral scan of the thoracolumbar spine. Calcium intake included total nutrient intake and total dietary supplements. The total MET is the sum of the METs for each activity (Vigorous/ moderate work-related activities, walking or bicycling for transportation and vigorous/ moderate recreational activities). Univariate and multivariate logistic regression analyses were utilized to investigate the effect of calcium intake, MET, and their combined effect on vertebral fracture.

RESULTS

A total of 766 participants were included in the analysis, and 54 participants had vertebral fractures. The median calcium intake and MET were 8.43 mcg and 280.00, respectively. Multivariate results showed that neither calcium intake nor MET as continuous or categorical variables was significantly associated with vertebral fractures. MET < 160 and calcium intake ≥ 670 mg group was associated with the decreased risks of vertebral fracture [odds ratio (OR) = 0.47, 95% confidence interval (CI): 0.26-0.83, P = 0.032] after adjusting for age, race, energy, total femur bone mineral density (BMD), and femoral neck BMD. In the group of MET < 160, increased calcium intake was associated with a reduced risk of vertebral fracture, with a decreased OR value. In the group of MET ≥ 160, increased calcium intake was associated with an increased risk of vertebral fracture, with an increased OR value.

CONCLUSION

The combination of MET < 160 and calcium intake ≥ 670 mg was associated with decreased risks of vertebral fractures. There may be an interaction between calcium intake and MET on vertebral fracture risk.

Adequacy of calcium and vitamin D nutritional status in a nationally representative sample of Irish teenagers aged 13-18 years

CONTEXT AND PURPOSE

In light of the key roles of vitamin D and calcium in adolescent bone health, there is a critical need for representative data on nutritional status for both micronutrients in teenagers. The present work used data from the recent representative National Teens' Food Survey II (2019-2020) to assess calcium and vitamin D intakes of teenagers in Ireland, including adequacy of such intakes, as well as, for the first time, to characterise serum 25-hydroxyvitamin D (25(OH)D) concentrations and their determinants.

METHODS

Usual calcium and vitamin D intake estimates were generated using food intake data (via 4-day weighed food records) from a nationally representative sample of teenagers aged 13-18 years in Ireland (n 428). Serum 25(OH)D was measured (via LC-MS/MS) in the 57.5% (n 246) who provided a blood sample.

RESULTS

Sixty-seven and 94% of Irish teenagers had intakes of calcium and vitamin D below the respective Estimated Average Requirements values, reflecting a high degree of inadequacy of intake for both micronutrients (and higher in girls than boys; P < 0.001). In addition, 21.7% and 33.1% of teenagers had serum 25(OH)D < 30 nmol/L (risk of vitamin D deficiency) and 30-49.9 nmol/L (inadequacy), respectively. Extended winter sampling, being aged 16-18 years, low total vitamin D intake, being overweight/obese or being of non-white skin type were significant (P < 0.05) predictors of serum 25(OH)D < 30 nmol/L.

CONCLUSIONS

There was a high prevalence of inadequacy of intake of calcium and vitamin D in Irish teenagers, and a fifth were at increased risk of vitamin D deficiency.

Dietary calcium intake in relation to blood lipids and lipoproteins profiles: A systematic review and meta-analysis of epidemiologic studies

AIMS

Findings of prior investigations on the association between calcium intake and lipid profiles were inconsistent. We performed a systematic review and meta-analysis on epidemiologic studies to evaluate the relationship of dietary calcium intake with blood lipids and lipoproteins.

DATA SYNTHESIS

A systematic search up to April 2021 was performed in different electronic databases, including MEDLINE (PubMed), Scopus, Web of Science (ISI), and Google Scholar for epidemiological studies that considered dietary calcium intake as the exposure and reported risk of dyslipidemia or blood lipids and lipoproteins concentrations (as mean ± SD or mean ± SE or median (Inter Quartile Range) as the outcomes of interest in adult populations from both genders (18 years or older), regardless of their health status. Nineteen cross-sectional studies were included in the analysis. Combining estimates from 11 studies (including 33,304 subjects) revealed that individuals in the highest category of calcium intake, compared to the lowest one, had 5.94 mg/dL lower circulating triglyceride (TG) concentration (weighted mean difference (WMD): -5.94; 95% CI: -8.27, -3.62), 4.02 mg/dL lower circulating low-density lipoprotein cholesterol (LDL-c) levels (WMD: -4.02; 95% CI: -7.08, -0.95), and 1.56 mg/dL higher blood high-density lipoprotein cholesterol (HDL-c) (WMD: 1.56; 95% CI: 0.81, 2.30). Although meta-analysis on 13 studies (including 38,714 participants) did not reveal a significant relationship between dietary calcium intake and odds of dyslipidemia or hyperlipidemia in the whole population, the highest vs. lowest level of calcium intake was related to 42% decreased odds of low blood HDL-c levels in females (95% CI: 0.40, 0.84) and 41% increased odds in males (95% CI: 1.21, 1.65).

CONCLUSIONS

This meta-analysis demonstrated that individuals with the highest dietary calcium intake might have lower blood TG, LDL-c, and higher HDL-c concentrations as compared to those with the lowest calcium intake. However, the linkage between dietary calcium intake with odds of hyperlipidemia or dyslipidemia was not significant. Because of the cross-sectional nature of included studies, causality could not be proven. Further prospective studies are needed to affirm these findings.

U-shaped association between dietary calcium density intake during adolescence and hypertension in adulthood: a 20-year longitudinal nationwide study in China

We assessed longitudinal association between calcium intake during adolescence and hypertension in adulthood. Longitudinal study data of 1611 participants from the China Health and Nutrition Survey during 1991-2011 were used. On average they were followed for 11·4 years. Dietary calcium intake during adolescence was assessed based on three 24-hour dietary recalls collected in each visit/survey between 1991 and 2009 (seven waves). The intake was recoded into quartiles. Cumulative mean±SD calcium intake was 199·9±144·8 mg/1000 kcal/day during adolescence. In total 102 participants had hypertension in adulthood (97 men and 5 women). There was a clear U-shaped association between adolescence calcium intake quartiles and adulthood hypertension: across the quartiles, hypertension prevalence was 6·7%, 4·0%, 5·2% and 9·5%, respectively. After adjustment for potential confounders including weight status and dietary pattern, odds ratios (OR, 95% CI) for hypertension were 2·32 (95% CI 1·07-5·00) for lowest quartile, 1·00 (reference), 1·34 (95% CI 0·61-2·97), and 3·10 (95% CI 1·49-6·46) across the quartiles. Lower or higher calcium intake during adolescence was associated with hypertension in adulthood independent of weight status and dietary pattern.

Effectiveness of an osteoporosis prevention educational program in Tunisian premenopausal women working in sedentary occupations: a quasi-experimental study

The objective of this study was to examine the effectiveness of an osteoporosis prevention program on knowledge and perception of self-efficacy in adopting preventive osteoporosis behaviors in premenopausal women working in sedentary occupations. Results show the improvement in knowledge and self-efficacy was statistically significant respectively (p < 0.001) and (p = 0.001).

INTRODUCTION

The main purpose of the study was to evaluate the effectiveness of an osteoporosis prevention educational program on knowledge and perception of self-efficacy in adopting preventive osteoporosis behaviors in Tunisian premenopausal women working in sedentary occupations.

METHODS

A quasi-experimental pre-post intervention study design. Our study population was composed of female employees, aged 35-50 years, of a company located in the industrial zone Sousse, situated in the center East of Tunisia. Three data collection methods were used: a questionnaire exploring socio-demographic characteristics and anthropometric measures, the Osteoporosis Knowledge Test, and the Osteoporosis Self-Efficacy Scale. The intervention consisted of an educational program relating to the promotion of calcium intake and physical activity. We are referred to the "Health Belief Model."

RESULTS

A survey conducted on 97 women. Only 81 subjects completed the study and are included in data analyses. The total knowledge score regarding osteoporosis improved by + 14.57 which corresponds to percentage of 109% between the pre- (T1) and post-test (T2). This improvement in knowledge was statistically significant (p < 0.001), going from 13.41 ± 3.94 at T1 to 27.98 ± 2.49 at T2. The total osteoporosis self-efficacy score has increased by + 9.56, or a percentage of 15% between the pre- and post-test. This improvement in self-efficacy was statistically significant (p = 0.001), going from 64.18 ± 20.84 at T1 to 73.73 ± 14.35 at T2.

CONCLUSION

It is important to create an appropriate environment for the adoption of favorable behaviors to healthy bones and to promote health education with political commitment and collaboration with different sectors.

Vitamin D Status of School-Age Children in North India

Information on vitamin D deficiency in prepubertal children is scarce. The authors studied calcium intake, sunlight exposure, serum calcium, alkaline phosphatase, 25-hydroxyvitamin (25OHD), and intact parathormone (iPTH) in the children (N = 135) attending the pediatric endocrinology clinic (declared normal after evaluation) and their healthy siblings. Serum 25OHD < 12 ng/mL was frequent (55.6%) and median (IQR) 25OHD lower [10.1 (11.4) ng/mL] in pubertal (n = 36) versus prepubertal (n = 99) children [36.4% (p < 0.05), 15.5 (13.2) ng/mL (p < 0.001)]. Girls had lower 25OHD [12.33 (10.32)] vs. [15.83 (13.37) ng/mL, p < 0.05], calcium intake [517.20 (405.5) vs. 623.6 (430.5) mg, p < 0.05], and minutes of sunlight exposure [MSE, 38.55 (42.86) vs. 63.4 (66.8) min, p < 0.01] than boys. MSE and body surface area (BSA) exposed were significant associations of 25OHD in a multivariate model. Vitamin D deficiency in children, both pubertal and prepubertal, assumes public health importance in the authors' region. Girls are at higher risk. Duration of sunlight exposure and BSA are modifiable factors.

How much do patients know about osteoporosis? A survey among patients referred to the dual-energy X-ray absorptiometry exam

BACKGROUND

Inadequate osteoporosis education can make patients ill-informed concerning preventive and therapeutic interventions and creates misconceptions and unnecessary concerns about the disease.

AIM

Our study aimed to assess whether patients referred to the DXA exam by their general practitioner are informed about risk factors for osteoporosis, comparing patients who received a diagnosis of osteoporosis before the exam with those without this diagnosis.

METHODS

An observational single-center study was performed among patients who were referred to the DXA exam at the Osteoporosis Service of Marche Nord Hospital (Fano, Italy) between April and July 2019. Socio-demographic and clinical characteristics, awareness of suffering from osteoporosis, femoral and lumbar spine T-score and bone mineral density, risk of fracture and the I-FOOQ score were assessed.

RESULTS

A pilot study was carried out to validate the questionnaire in the Italian language (alpha-Cronbach 0.75). After that, a sample of 128 patients was enrolled (response rate 93.3%). Mean age was 66 ± 10.6 years, 95.6% were women. Overall, I-FOOQ mean score was 12 ± 3.5. Age, educational level, menopausal age, body mass index, femoral T-score were not associated with a better knowledge (p > 0.05). A comparison between who know to suffer from osteoporosis and others found no differences (12.2 ± 3.4 and 12 ± 3.5, respectively, p = 0.772). Effect of walking, recommended calcium intake, and familiar predisposition are the less known topics.

CONCLUSION

Patients who undergo the DXA exam are poorly informed about risk factors for osteoporosis, independently of age, education, bone mineral density and risk of fracture. Knowing to suffer from osteoporosis does not increase the likelihood to be informed. It is mandatory to improve the education that is provided to the patients, as there are effective non-pharmacological interventions to prevent and treat osteoporosis.

Lack of calcium rich foods in the diet, low knowledge on calcium level recommendations and severe food insecurity predicts low calcium intake among Vietnamese women

OBJECTIVE

To assess nutrition knowledge related to osteoporosis and calcium, osteoporosis health beliefs, dietary calcium intake and household food insecurity among adult women in Vietnam.

METHODS

Two hundred fifty-one women aged 30-65 years living in a rural district in Hanoi -Vietnam were recruited. A questionnaire was used to collect information on nutrition knowledge related to osteoporosis and calcium intake, health beliefs, household food security, and dietary calcium intake. Data analysis included descriptive statistics and regressions.

RESULTS

Majority of the participants did not know calcium recommendations (95%) and recommended daily servings of calcium-rich foods (60%). In addition, majority of the participants (83.7%) were not aware of osteoporosis risk factors. Slightly less than half of the participants (46.2%) reported that they would have difficulties changing their current diets to consume more calcium rich foods. Half of the participants (50.4%) reported being food insecure, with 22% of them reporting having severe food insecurity. Mean dietary calcium intake was 534.5 mg/day, of which milk and dairy products contributed only 4%. Nutrition knowledge, perceived benefits, and self-efficacy were positively associated with calcium intake (p < 0.05); whereas perceived barriers and severe food insecurity were significantly associated with low dietary calcium intake (p < 0.05).

CONCLUSIONS

The results of this study showed calcium intake among the participating Vietnamese women was lower than the national recommendation, indicating the need for nutrition programs and promotions to increase calcium intake. These programs should aim at increasing awareness on national calcium recommendations and skills to obtain and consume calcium-rich foods while considering development of safety nets for food insecure households, as pertaining to adequate dietary calcium intake.

Relationship between vitamin D receptor gene polymorphisms (BsmI, TaqI, ApaI, and FokI) and calcium intake on bone mass in young Japanese women

Background

The high prevalence of low bone mass in young women in Japan has emerged as a serious health issue in recent years. Therefore, the aim of the present study was to reevaluate the relationship between genetic and dietary factors, as well as its influence on bone mass in young Japanese women, with particular emphasis on vitamin D receptor (VDR) gene polymorphisms and calcium intake.

Methods

A total of 499 Japanese women aged 20–24 years were enrolled in the study. The bone mass of the calcaneus was assessed using the quantitative ultrasound method and expressed as the osteo sono-assessment index (OSI). VDR gene polymorphisms (BsmI, TaqI, ApaI, and FokI) were analyzed using DNA extracted from saliva. Calcium intake was assessed using the Food Frequency Questionnaire based on food groups (FFQg) and adjusted with the energy intake. Participants were divided into two groups based on the median calcium intake (250 mg/1000 kcal).

Results

Consequently, bone mass was significantly different among the BsmI and TaqI genotypes after adjusting for body mass index (BMI) (p = 0.030 and 0.019, respectively). In addition, the BsmI AA and ApaI GT genotypes showed significant differences in bone mass between the calcium-intake groups, with low OSI in the low-calcium intake group and high OSI in the high-calcium intake group, respectively, even after adjusting for BMI (p = 0.020 and 0.038, respectively).

Conclusions

These findings may prove instrumental in developing a logical approach towards preventing bone loss in young Japanese women.

Association of calcium intake, lactose intolerance and physical activity with bone health assessed via quantitative ultrasound among young adults of a Malaysian university

Lactose intolerance has been proposed to cause poor bone health. This study found the prevalence of lactose intolerance was high among Malaysian young adults, but not associated with bone health status, unlike calcium intake. This is the first study that investigated the association of lactose intolerance and bone health status in Malaysia.

PURPOSE

The aims of this study were to determine the prevalence of lactose intolerance, calcium intake and physical activity level and to investigate the association between these variables with bone health status among young adults.

METHODS

This cross-sectional study consisted of 300 Malay, Chinese and Indian students from Universiti Kebangsaan Malaysia with mean age of 22.5 ± 3.2 years. Determination of lactose tolerance status was performed using hydrogen breath test, lactose tolerance test and visual analogue scales. Calcium intake and physical activity level were evaluated using Food Frequency Questionnaire and International Physical Activity Questionnaire, respectively. Bone health status was assessed on calcaneal bone, using quantitative ultrasound.

RESULTS

Lactose intolerance was highly reported among the Malay subjects (72%) followed by Chinese (59%) and Indians (42%). The mean calcium intake was 542.9 ± 365.2 mg/day whilst the mean physical activity was 2757.6 ± 2007.2 MET-min/week. The bone assessment showed that 91% of the subjects had a low risk of developing osteoporosis. Only calcium intake showed a significant association with bone health status (β = 0.006; p = 0.033), whilst no association was shown for lactose intolerance and physical activity level.

CONCLUSIONS

Malaysian young adults showed a high prevalence of lactose intolerance. Calcium intake is associated with increased bone health status. In contrast, lactose intolerance and physical activity level did not directly influence bone health status. Nutrition education promoting adequate calcium intake should be implemented among young adults due to high lactose intolerance prevalence and low calcium intake among subjects.

Effect of Silicon Supplementation in Diets with Different Calcium Levels on Balance of Calcium, Silicon and Magnesium, and Bone Status in Growing Female Rats

Silicon (Si) is important for the growth and development of bone and connective tissues. This study aimed to evaluate the effect of Si supplementation on the balance of calcium (Ca), Si, magnesium (Mg), and bone status in growing female rats fed diets with different Ca levels. Sixty 6-week-old female Wistar rats were divided into 6 groups and fed diets with different levels of Ca (0.1, 0.5, 1.5%) and Si (5, 500 ppm) for 10 weeks. Experimental groups were as follows: Low-Ca group (LCa; 0.1% Ca), Low-Ca with Si supplementation group (LCaSi), adequate-Ca group (ACa; 0.5% Ca), adequate-Ca with Si supplementation group (ACaSi), high-Ca group (HCa; 1.5% Ca), and high-Ca with Si supplementation group (HCaSi). Si retention significantly increased by Si supplementation and significantly decreased by high-Ca diet (1.5%). Mg retention significantly decreased by high-Ca diet. Serum Ca and Si contents were not significantly different among the 6 groups. Low-Ca diet significantly increased serum osteoclain and C-telopeptide cross-link of type 1 collagen (CTx) levels, and Si supplementation significantly decreased CTx levels in the low-Ca diet group. Bone mineral density was significantly increased along with Ca increase in the diet, but was decreased by Si supplementation in the high-Ca diet. Rats in the adequate-Ca diet group had a significant increase in strength of tibia after Si supplementation. These findings indicate that the effect of Si supplementation on bone metabolism may differ according to the Ca-intake level in growing females. Although further research is needed, when supplementing Si to improve bone health in growing females, Ca-intake level should be considered.

Assessment of calcium intake and perception of calcium-rich food among healthcare students at King Saud bin Abdulaziz University for Health Science (KSAU-HS)

BACKGROUND

Calcium is an essential mineral compound and one of the most abundant minerals in the human body. A long-term low calcium intake predisposes the bones to fractures, osteopenia, and osteoporosis. This study was conducted to assess calcium intake and knowledge of calcium-related information among healthcare students in King Saud bin Abdulaziz University for Health Sciences (KSAU-Hs).

METHODS

This cross-sectional survey was conducted using a self-administered questionnaire that has been distributed as a soft copy of 289 participants aged 19 years or older and studied at KSAU-Hs. The questionnaire had three sections assessing demographical data, calcium knowledge, and calcium intake. The knowledge outcome variables were good and poor, and participants were categorized as good knowledge if they answer 11 or more of the 18 questions, while the intake outcome variables were sufficient and insufficient intake based on the Recommended Dietary Allowance (RDA) of 1000 mg.

RESULTS

Among all variables, 91.7% of the participants were found to be having an insufficient intake, and 74% were classified to be poor knowledge. As for knowledge, the highest score under the "Good" category were females 32.7% compared to males 22.2%, P = 0.05. The average intake of calcium was 497 mg/day. In terms of sufficient calcium intake, males scored 11.9% compared to females who scored 1.9% with a P value of 0.00.

CONCLUSION

The results of this study have shown that there are significantly insufficient calcium intake and poor knowledge about calcium among healthcare students. The results indicate the urge to improve calcium intake and calcium knowledge among the healthcare students.

Adequacy of calcium intake in Spanish population according age groups

This review shows the estimated calcium intake in Spain in recent years. Our results indicate that adolescents and the elderly are at risk of insufficient calcium intake. By using the national and the European recommendations, this work contributes to map and compare population's dietary calcium intake in the European countries. PURPOSE AND METHODS : The present work aims to examine calcium intake in the healthy Spanish population of any age and analyze its adequacy to the calcium Recommended Dietary Intake (RDI) for different groups in Spanish population, as well to the Adequate Intake (AI) or Population Reference Intake (PRI) estimated by European Food Safety Authority (EFSA). Forty-three studies published in the last 5 years were eligible for review. RESULTS AND CONCLUSIONS: The results show that infants and children exceed Spanish and EFSA dietary recommendations, adults meet more that 80% of the RDI and EFSA recommendations, and the estimated average calcium intake in the adolescent and elderly groups does not reach 75% of the recommended intake. Representative national studies with a common methodology to estimate calcium intake are needed.

Contribution of calcium in drinking water from a South American country to dietary calcium intake

Objective

To describe the calcium concentration of tap and bottled waters from Argentina and to estimate the contribution of drinking water to calcium recommendations.

Results

Calcium concentrations provided by water authorities ranged from 6 to 105 mg/L. The mean calcium level of samples analysed at the Laboratorio de Ingeniería Sanitaria, National University of La Plata was 15.8 (SD ± 13.2) mg/L and at the Bone Biology Laboratory of the National University of Rosario was 13.1 (± 10.0) mg/L. Calcium values of samples from supply systems and private wells was similar. Most bottled waters had calcium levels well below 50 mg/L. The intake of one litre of drinking water from Argentina could represent in average between 1.2 and 8.0% of the calcium daily values for an adult.

Calcium intake is inversely associated with body fat in postmenopausal women

BACKGROUND & AIMS

Calcium intake seems to be inversely associated with body fat in several populations; however, little is known about this relationship in postmenopausal women. This study aimed to associate calcium intake with body fat mass in postmenopausal women.

METHODS

A cross-sectional study was performed with 107 postmenopausal women who entered in a lifestyle change program. The dietary intake was estimated through three 24-h food recalls. Body fat mass was evaluated by dual-energy X-ray absorptiometry (DXA). Linear regression analyzes were performed associating body fat variables (total fat mass, body fat percentage, trunk fat, gynoid and android fat mass; and body mass index) with calcium intake.

RESULTS

After adjustments for age; carbohydrate, protein, lipids and fiber intakes; and physical activity, it was observed that calcium intake (mg/day) was inversely associated with total fat mass (kg and percentage), trunk fat mass (kg), gynoid and android fat mass (kg). Calcium intake was not associated with body mass index, although a tendency was observed (p = 0.062).

CONCLUSION

Calcium intake was inversely associated with body fat mass in postmenopausal women.

Adherence to the Recommended Intake of Calcium and Colorectal Cancer Risk in the HEXA Study

Purpose

Dietary calcium intake has been suggested to be protective against the development of colorectal cancer. The mean dietary calcium intake of Koreans is 490 mg/day, which is far below the recommended calcium intake of 700-800 mg/day. In this study, we explored the relationship between dietary calcium intake and colorectal cancer development in Koreans with relatively low calcium intake compared with individuals in Western countries.

Materials and Methods

The Health Examinees Study, a large-scale genomic community-based prospective cohort study, was designed to identify the general characteristics of major chronic diseases in Koreans. A total of 119,501 participants aged 40-69 years recruited between 2004 and 2013 were included in this analysis. The calcium intake level was categorized using the Dietary Reference Intakes for Koreans (KDRIs). The Cox proportional hazards regression model was used to estimate the hazard ratio (HR) and the corresponding 95% confidence intervals (CIs) for colorectal cancer risk, adjusting for potential confounders.

Results

In the multivariable-adjusted model, compared with the group that consumed less than the recommended amount of calcium, the group that consumed more than the recommended intake of calcium showed a significant reduction in the risk of colorectal cancer in women. (HR, 0.54; 95% CI, 0.31 to 0.95). Among men, however, no significant association was observed between dietary calcium intake and colorectal cancer risk (HR, 0.89; 95% CI, 0.54 to 1.45).

Conclusion

Korean women who adhere to the recommended intake of calcium showed a reduced risk of colorectal cancer.

Association between pre-pregnancy calcium intake and hypertensive disorders during the first pregnancy: the Japan environment and children's study

BACKGROUND

Determining the appropriate preconception care to reduce the occurrence of hypertensive disorder of pregnancy (HDP) remains a challenge in modern obstetrics. This study aimed to examine the association between pre-pregnancy calcium (Ca) intake and HDP in normotensive primiparas.

METHODS

We used data from the Japan Environment Children's study (JECS), which is the largest birth cohort study. A total of 33,894 normotensive Japanese primiparas were recruited for JECS between January 2011 and March 2014. Participants were categorized into five groups according to pre-pregnancy Ca intake quintiles (Q1 and Q5 were the lowest and highest Ca intake groups, respectively) to compare their basic background and obstetrics outcome. Multiple logistic regressions were performed to identify the effect of pre-pregnancy Ca intake on HDP, early onset HDP, and late-onset HDP, using Ca intake thresholds of 500, 550, 650, 700, 1000, 1500, and 1500 mg.

RESULTS

We found significant differences in maternal background among the Ca intake groups; in particular, there were more participants with low socioeconomic status, indicated by low education level and low household income, and smokers in the lowest Ca intake group. Multiple logistic regression did not show any significant difference with regard to HDP, early onset HDP, and late-onset HDP in each Ca intake threshold.

CONCLUSIONS

Despite considerable recommendations concerning Ca intake for women of reproductive age, the present study indicates that pre-pregnancy Ca intake was not associated with an increased risk of new-onset hypertension among primiparas during pregnancy. Further studies examining the effect of other pre-pregnancy dietary factors on obstetric outcomes should be considered in the formulation of earlier preventive strategies for primiparas.

Calcium intake in Colombia: are we still in deficit?

This study describes the median average intake of calcium in a population in Bogota, Colombia. Approximations on the possible reasons of low intake are listed.

INTRODUCTION

The International Osteoporosis Foundation (IOF) published in 2017 the Calcium Map. It is a review of the calcium intake of 74 countries, placing Colombia in the bottom three countries of the world, with a daily calcium intake of 297 mg per day. The present study determined the actual median average calcium intake of a sample from Bogota and described it using sociodemographic variables.

METHODS

In 2019, 450 anonymous volunteers who agreed to fill out the IOF Calcium Calculator survey were recruited. Measures of frequencies and percentage for qualitative variables were used, along with measures of central tendency with averages and dispersion for quantitative variables. Insufficient daily calcium intake was determined according to age, gender, and overall.

RESULTS

The median average intake was 726 mg/day. Population between 18 and 30 years old had the highest intake per day. There were no significant differences between genders: women had a median average calcium intake of 731 mg/day, and for men it was 717.5 mg/day. Intake was directly correlated with socioeconomic status.

CONCLUSIONS

Calcium intake in Colombia is low according to the age requirements and it is proportional to the socioeconomic status. Medical societies and national government should create policies in order to educate the general public and increase the intake of calcium based on diet.

Adult lactose intolerance, calcium intake, bone metabolism and bone density in German-Turkish immigrants

INTRODUCTION

Adult lactose intolerance (ALI) significantly alters calcium intake and absorption, and thus may promote osteoporosis. ALI is a recessive condition with a geographical north-south gradient characterised by decreased levels of intestinal lactase. PCR-based genotyping of lactase (LCT) gene polymorphisms is a safe and easy way to diagnose ALI and may complement diagnostic procedures to identify individuals at risk for reduced calcium intake and subsequently osteoporosis due to lactose malabsorption. Therefore, we investigated the frequency of ALI and its influence on calcium intake, markers of bone metabolism and bone mineral density (BMD) in a cohort of Turkish immigrants living in Germany.

MATERIALS AND METHODS

We investigated single nucleotide polymorphisms of the LCT gene, calcium intake, markers of bone metabolism and BMD in 183 Turkish immigrants.

RESULTS

ALI was diagnosed in 154 out of 183 (81%) probands. ALI was significantly associated with self-reported lactose intolerance (p < 0.001) and dislike for dairy products (p < 0.01). Osteopenia was diagnosed in 59 out of 183 (32%) and osteoporosis in 15 out of 183 (8%) probands. Probands with reduced BMD had ALI in 86%. All probands had a decreased calcium intake [mg/week]. There was no significant association between ALI, calcium intake, markers of bone metabolism or BMD.

CONCLUSION

Turkish immigrants mostly have ALI and overall show a reduced calcium intake per week. However, ALI did not significantly influence calcium intake, markers of bone metabolism or BMD in this cohort. Therefore, ALI in Turkish immigrants does not seem to be a risk factor for osteoporosis.

Probiotic Lactobacillus strains from Mongolia improve calcium transport and uptake by intestinal cells in vitro

The aim of this study was to investigate the probiotic properties of 174 Lactobacillus strains isolated from Mongolian dairy products, and particularly their impact on intestinal calcium uptake and absorption. All isolates underwent a first screening based on cell surface hydrophobicity, acid tolerance, tolerance to gastro-intestinal digestion, autoaggregation, adhesion and cytotoxicity against intestinal cells. Six Lactobacillus strains from different species (L. casei, L. kefiranofaciens, L. plantarum, L. fermentum, L. helveticus and L. delbrueckii) were selected, and their impact on intestinal calcium uptake and transport was investigated using Caco-2. Five strains were able to improve total calcium transport after 24 h contact with a differentiated Caco-2 cell monolayer. Concomitantly the L. plantarum strain was able to increase cellular calcium uptake in Caco-2 cells by 10% in comparison to control conditions. To determine which pathway(s) of calcium absorption was modulated by the strains, a qPCR-based study on 4 genes related to calcium/vitamin D metabolism or tight junction integrity was conducted on mucus-secreting intestinal HT-29 MTX cells. The L. plantarum strain modulates the transcellular pathway by regulating the expression of vitamin D receptor (1.79 fold of control) and calcium transporter (4.77 fold of control) while the L. delbrueckii strain acts on the paracellular pathway by modulating claudin-2 expression (2.83 fold of control). This work highlights the impact of Lactobacillus probiotic strains on intestinal calcium absorption and for the first time give some evidence about the cellular pathways involved.

Calcium intake in an adult Ukrainian population

This is a first large epidemiological study of calcium intake in Ukrainian population. The data from 1518 outpatient subjects aged 20-89 years old showed that the mean level of calcium intake composed 615.6 mg/day (735.4 mg/day in males and 565.6 mg/day in females, p < 0.0001) without any significant differences according to age.

INTRODUCTION

Insufficiency in calcium (Ca) intake is a worldwide problem; however, corresponding data regarding Ukrainian population is limited. This research was aimed to investigate the level of Ca consumption in daily rations of Ukrainian adults depending on age and sex.

METHODS

The data from 1518 outpatient subjects from urban and rural areas of Ukraine were analyzed; the Ca intake was evaluated by the method of 24-h dietary recalls during three non-consecutive days by a trained dietitian with further computer calculation.

RESULTS

The mean level of Ca intake in Ukrainian population composed 615.6 mg/day (735.4 mg/day in males and 565.6 mg/day in females) with significantly higher level of consumption in men than in women in whole group and in the subjects aged 50 years and more. In total, 67% of men and 78% of women consumed less than 800 mg/day Ca and only 28% of males and 10% of females consumed more than 1000 mg/day Ca.

CONCLUSIONS

This is a first large epidemiological study of Ca intake in Ukrainian population which confirmed its low level. This insufficiency in Ca intake can have a negative influence on exaggerated bone loss, osteoporosis development, and fracture risk that require forehanded correction.

Calcium intake from diet and supplement use during early pregnancy: the Expect study I

PURPOSE

Adequate calcium intake during pregnancy is of major importance for the health of both mother and fetus. Up to date, evidence on the prevalence of inadequate calcium intake among pregnant women is sparse for Western countries, and it is unknown to what extent inadequate dietary calcium intake is adequately balanced by supplement use. The objective of this study was to estimate calcium intake from diet and supplement use during the early pregnancy in The Netherlands.

METHODS

As part of the Expect cohort study, 2477 pregnant women (8-16 weeks of gestation) completed an online questionnaire including questions on baseline characteristics, the use of calcium containing supplements, and a short food-frequency questionnaire (FFQ). Intake data were used to calculate median calcium intakes from diet, from supplements, and combined, and to compare these values with currently accepted requirement levels.

RESULTS

Forty-two percent of the pregnant women had a total calcium intake below the estimated average requirement of 800 mg/day. Median (interquartile range) calcium intake was 886 (611-1213) mg/day. Calcium or multivitamin supplements were used by 64.8% of the women at 8 weeks of gestation, with a median calcium content of 120.0 (60.0-200.0) mg/day. Prenatal vitamins were the most often used supplements (60.6%).

CONCLUSIONS

Forty-two percent of Dutch pregnant women have an inadequate calcium intake. Supplements are frequently used, but most do not contain sufficient amounts to correct this inadequate intake.

Dairy- and supplement-based calcium intake in adulthood and vertebral dimensions in midlife-the Northern Finland Birth Cohort 1966 Study

Among a representative sample of 1064 Northern Finns, we studied the association of dairy- and supplement-based calcium intake in adulthood with vertebral size in midlife. Inadequate calcium intake (< 800 mg/day) from age 31 to 46 predicted small vertebral size and thus decreased spinal resilience among women but not men.

INTRODUCTION

Small vertebral size predisposes individuals to fractures, which are common among aging populations. Although previous studies have associated calcium (Ca) intake with enhanced bone geometry in the appendicular skeleton, few reports have addressed the axial skeleton or the vertebrae in particular. We aimed to investigate the association of dairy- and supplement-based Ca intake in adulthood with vertebral cross-sectional area (CSA) in midlife.

METHODS

A sample of 1064 individuals from the Northern Finland Birth Cohort 1966 had undergone lumbar magnetic resonance imaging at the age of 46, and provided self-reported data on diet and Ca intake (dairy consumption and use of Ca supplements) at the ages of 31 and 46. We assessed the association between Ca intake (both continuous and categorized according to local recommended daily intake) and vertebral CSA, using generalized estimating equation and linear regression models with adjustments for body mass index, diet, vitamin D intake, education, leisure-time physical activity, and smoking.

RESULTS

Women with inadequate Ca intake (< 800 mg/day) over the follow-up had 3.8% smaller midlife vertebral CSA than women with adequate Ca intake (p = 0.009). Ca intake among men showed no association with vertebral CSA.

CONCLUSIONS

Inadequate Ca intake (< 800 mg/day) from the age of 31 to 46 predicts small vertebral size and thus decreased spinal resilience among middle-aged women. Future studies should confirm these findings and investigate the factors underlying the association of low Ca intake in women but not in men with smaller vertebral size.

Assessment of research waste part 1: an exemplar from examining study design, surrogate and clinical endpoints in studies of calcium intake and vitamin D supplementation

BACKGROUND

Research waste is estimated to be very common, but assessments of its prevalence and scope are rare. As an example, we assessed research waste in clinical research on calcium intake (assessing study design and endpoint type) and vitamin D supplementation (assessing endpoint type).

METHODS

We examined 404 randomised controlled trials (RCTs) and observational studies of calcium intake (diet or supplements) and bone mineral density (BMD) or fracture, and 547 RCTs of vitamin D supplements, and assessed the proportion of studies that used surrogate or clinical endpoints. For studies with BMD or fracture as an endpoint, we estimated when the 'tipping' point occurred indicating the need for RCTs with fracture as an endpoint (based on cumulative meta-analyses of BMD RCTs, and chronological review of observational studies), and whether each study published at least 5y after the tipping point was novel, added new clinical knowledge or was research waste.

RESULTS

Observational studies of calcium intake and BMD or fracture outnumbered RCTs by 3.3-4.5 times. For both calcium intake and vitamin D supplements, studies using surrogate endpoints outnumbered studies using clinical endpoints by 1.6-3 times. Of 41 RCT publications of calcium intake and BMD or fracture published at least 5y after the tipping point in 1994, we considered that 19 (46%) lacked novelty, another 13 (32%) added no new clinical knowledge, and 30 (73%) were research waste. Of 204 observational study publications of calcium intake and BMD or fracture, 197 (96%) lacked novelty, another 5 (2%) added no new clinical knowledge, and 202 (99%) were research waste. Of 39 RCTs of vitamin D supplementation and BMD or fracture published at least 5y after the tipping point in 1999, 14 (36%) lacked novelty, another 13 (33%) added no new clinical knowledge, and 27 (69%) were research waste.

CONCLUSIONS

A high proportion of studies of calcium intake since 2000 (95%) and trials of vitamin D supplements since 2005 (69%) on BMD or fracture represent research waste.

Decrease of Estradiol and Several Lifestyle Factors, but Not Helicobacter pylori Infection, Are Significant Risks for Osteopenia in Japanese Females

BACKGROUND

The primary cause of osteoporosis in women is increased bone resorption and decreased bone density associated with reduced estrogen secretion. Several studies have demonstrated a relationship between Helicobacter pylori infection and osteoporosis regardless of estrogen levels. This study examined the relationship between H. pylori infection and osteopenia together with estrogen levels, calcium intake, and several lifestyle factors.

METHODS

This study included 473 healthy women who underwent a general health examination. Multivariate analysis was performed, with age, body mass index (BMI), smoking habit, drinking habit, exercise habit, schooling duration, estradiol levels, birth history, calcium intake, schooling duration, smoking habit, drinking habit, exercise habit, and H. pylori infection as independent variables and the presence of osteopenia as a dependent variable.

RESULTS

The adjusted OR for osteopenia with H. pylori infection was 0.95 (95% CI 0.55-1.63, p = 0.84). In contrast, osteopenia was significantly associated with age, low BMI, lesser schooling period, low estradiol levels, and low calcium intake.

CONCLUSIONS

H. pylori infection was not a significant risk for osteopenia by the multivariate analysis, which included the primary confounding factors. Significant factors, such as estradiol and calcium intake, should be assessed together to study the association of H. pylori infection and osteopenia.

Assessment of dietary calcium intake of university students: a pilot study in Turkey

The aim of this study was to adapt the rapid assessment method (RAM) and International Osteoporosis Foundation Food Frequency Questionnaire (IOF FFQ) tools, used for the assessment of daily calcium intake in university students, and to compare the data obtained using 24-h recall (24-HR) data. There was a moderate positive correlation between the RAM and IOF.

PURPOSE/INTRODUCTION

Calcium is an essential mineral that plays vital roles in metabolism and it is very important to accurately assess the amount of calcium intake on the diet. It was aimed to assess the daily calcium intake of university students by two different food frequency questionnaires (FFQs) developed specifically for evaluating calcium intake, and 24-h recall method.

METHOD

The study was conducted with a total of 183 female university students aged 18-31. In the study, a questionnaire including sociodemographic information, a calcium calculator, IOF FFQ, prepared in seven different languages, and RAM was applied. In addition, 1-day food consumption records were obtained using 24-HR method.

RESULTS

The daily average calcium intakes of individuals according to two different food frequency questionnaires (RAM FFQ and IOF FFQ) and 24-h food consumption records are respectively 1594.2 ± 810.9, 897.9 ± 368.4, and 605.6 ± 278.3 mg. When the daily average calcium intake was compared with the other two methods, RAM was found to be statistically higher (p < 0.001). There was a moderate positive correlation between the RAM and IOF FFQ methods (Pearson r = 0.528, p < 0.01) and the intra-class correlation coefficient between these two methods was found to be significant and moderate (ICC r = 0.452, p < 0.01).

CONCLUSION

In terms of protecting and improving health, it is important to make suggestions using fast and short tools to ensure adequate calcium intake from young age. It is thought that FFQs are the most appropriate methods in assessing daily calcium intake for this study group because it is observed that the list of foods and the amount of portions in FFQs reduce the problem of remembering at 24-h method to a great extent.

High phosphorus intake and gut-related parameters - results of a randomized placebo-controlled human intervention study

Background

In recent years, high phosphate intakes were discussed critically. In the small intestine, a part of the ingested phosphate and calcium precipitates to amorphous calcium phosphate (ACP), which in turn can precipitate other intestinal substances, thus leading to a beneficial modulation of the intestinal environment. Therefore, we analysed faecal samples obtained from a human intervention study regarding gut-related parameters.

Methods

Sixty-two healthy subjects (men, n = 30; women, n = 32) completed the double-blind, placebo-controlled and parallel designed study (mean age: 29 ± 7 years; mean BMI: 24 ± 3 kg/m²). Supplements were monosodium phosphate and calcium carbonate. During the first 2 weeks, all groups consumed a placebo sherbet powder, and afterwards a sherbet powder for 8 weeks according to the intervention group: P1000/Ca0 (1000 mg/d phosphorus), P1000/Ca500 (1000 mg/d phosphorus and 500 mg/d calcium) and P1000/Ca1000 (1000 mg/d phosphorus and 1000 mg/d calcium). After the placebo period and after 8 weeks of intervention faecal collections took place. We determined in faeces: short-chain fatty acids (SCFA) and fat as well as the composition of the microbiome (subgroup) and cyto- and genotoxicity of faecal water (FW). By questionnaire evaluation we examined tolerability of the used phosphorus supplement.

Results

Faecal fat concentrations did not change significantly due to the interventions. Concentrations of faecal total SCFA and acetate were significantly higher after 8 weeks of P1000/Ca500 supplementation compared to the P1000/Ca0 supplementation. In men, faecal total SCFA and acetate concentrations were significantly higher after 8 weeks in the P1000/Ca1000 group compared to the P1000/Ca0 one. None of the interventions markedly affected cyto- and genotoxic activity of FW. Men of the P1000/Ca1000 intervention had a significantly different gut microbial community compared to the men of the P1000/Ca0 and P1000/Ca500 ones. The genus Clostridium XVIII was significantly more abundant in men of the P1000/Ca1000 intervention group compared to the other groups. Supplementations did not cause increased intestinal distress.

Conclusions

The used high phosphorus diet did not influence cyto- and genotoxicity of FW and the concentrations of faecal fat independent of calcium intake. Our study provides first hints for a potential phosphorus-induced modulation of the gut community and the faecal total SCFA content.

Trial registration

The trial is registered at ClinicalTrials.gov as NCT02095392.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0331-4) contains supplementary material, which is available to authorized users.

Development and psychometric properties of a Calcium Intake Questionnaire based on the social cognitive theory (CIQ-SCT) for Iranian women

Background: Osteoporosis is common among women which may be mostly due to the low intake of calcium. This article reports the development, cultural adaptation and psychometric properties of a Calcium Intake Questionnaire based on the social cognitive theory (CIQ-SCT)among Iranian women.

Methods: In 2016, this cross-sectional study was carried out among 400 younger than 50 years old women in Isfahan, Iran. After literature review, a preliminary 35-item questionnaire was developed. Then, forward-backward translation and cultural adaptation of the tool was conducted. Content Validity Index confirmed by an expert panel and Face Validity was evaluated in a pilot study. Exploratory and confirmatory factor analyses (EFA &CFA) were conducted on the calibration and validation sample, respectively. Reliability was also assessed using internal consistency test.

Results: After determining content and face validity, 20 items with 5 factors (self-efficacy,outcome expectations, social support and self-regulation) were obtained. Cronbach alpha for the instrument was found to be 0.901. In EFA, we identified a 4-factor model with a total variance of 72.3%. The results related to CFA (CMIN/DF=1.850, CFI =0.946, TLI=0.938, RMSEA=0.069[90% CI: 0.057-0.081]) indicated that the model was fit to the social cognitive theory. Self regulation was detected as the best predictor for calcium intake.

Conclusion: The CIQ-SCT showed acceptable levels of reliability and validity in explaining the calcium intake based on the constructs of social cognitive theory. Further psychometric testing is recommended in different population to approve the external validity of the instrument.

Calcium intake, bone mineral density, and fragility fractures: evidence from an Italian outpatient population

This study was performed in 1000 adult Italian subjects to focus on the effects of dietary calcium intake on bone health. A higher fracture risk appears to be associated with a reduced calcium intake. An adequate daily calcium intake is recommended to counteract osteoporotic fractures.

PURPOSE

The principal aim of the present study was to focus on the effects of dietary calcium intake on bone mineral density (BMD) and fragility fractures in a representative sample of an adult Italian outpatient population.

METHODS

The study group consisted of 1000 consecutive adult Italian subjects [838 women (F) and 162 men (M)] referred to the Bone Metabolic Diseases Unit for the evaluation of their bone metabolism. Daily dietary calcium intake was assessed using a specific food frequency questionnaire (FFQ). Other evaluations included fracture risk, lumbar and femoral BMD, heel ultrasound, fragility fractures, plasma concentration of parathyroid hormone ([PTH]) and 25-hydroxy-vitamin D ([25(OH)D]), and urinary calcium.

RESULTS

Only 10.4% of the subjects (n = 104; 71 F and 33 M) had a daily calcium intake adequate for adults (≥1000 mg/day). No correlation was found between calcium intake and BMD. The transition from a daily dietary calcium intake <400 mg/day to a daily dietary calcium intake ≥400 mg/day was associated with a reduced fracture probability ratio at any site [from 42 to 21% (p < 0.05)]. Subjects with one or more vertebral fractures had a significantly lower dietary calcium intake (<400 mg/day) than did subjects without vertebral fractures, and they practiced physical activity only occasionally (p = 0.030).

CONCLUSIONS

Daily dietary calcium intake is lower than the recommended daily intake in an Italian ambulatory population, and a higher fracture risk appears to be associated with a reduced calcium intake. An age-adequate daily calcium intake, combined with regular physical activity, is strongly recommended in order to counteract fragility fractures.

Impact of air pollution on vitamin D deficiency and bone health in adolescents

The association between air pollution and bone health was evaluated in adolescents in the city of Tehran. This study is essentially ecological. Vitamin D deficiency among adolescents has been reported at higher rates in polluted areas than in non-polluted areas. Additionally, residence in polluted areas is associated with lower levels of bone alkaline phosphatase.

PURPOSE

The aim of this study was to evaluate the association between ambient air pollution and bone turnover in adolescents and to compare the prevalence of vitamin D deficiency between polluted and non-polluted areas of Tehran.

METHODS

This cross-sectional population-based study was conducted on 325 middle- and high-school students (both girls and boys) in Tehran in the winter. During the study period, detailed daily data on air pollution were obtained from archived data collected by Tehran Air Quality Control Company (AQCC). Serum levels of calcium, phosphorus, parathyroid hormone (PTH), bone-specific alkaline phosphatase, 25(OH) vitamin D, osteocalcin, cross-linked C-telopeptide (CTX), total protein, albumin, and creatinine were obtained from the study group.

RESULTS

Vitamin D deficiency was more prevalent in polluted areas than in non-polluted areas. After adjustment for age and sex, residence in the polluted area showed a statistically significant positive association with vitamin D deficiency and a statistically significant negative association with bone turnover. Interestingly, high calcium intake (>5000 mg/week) protects against the effects of air pollution on bone turnover.

CONCLUSIONS

Air pollution is a chief factor determining the amount of solar UVB that reaches the earth's surface. Thus, atmospheric pollution may play a significant independent role in the development of vitamin D deficiency.

Dietary factors and fibroblast growth factor-23 levels in young adults with African ancestry

Fibroblast growth factor-23 (FGF23), a phosphaturic hormone secreted mainly by osteocytes, maintains serum phosphate levels within a tight range by promoting phosphaturia. Previous studies have mainly focused on the link between FGF23 levels and dietary intake of phosphate, but other dietary factors may also influence FGF23 levels. This cross-sectional study pooled three populations of young adults with African ancestry (452 in Chicago, IL, USA; 477 in Victoria, Seychelles; and 482 in Kumasi, Ghana) with estimated glomerular filtration rate >80 ml/min/1.73 m² to examine the association of dietary factors based on two 24-h recalls with FGF23 levels measured using a C-terminal assay. Linear regression was used to examine the association between log-transformed FGF23 levels and quartiles of calorie-adjusted dietary factors with adjustment for covariates. In the pooled sample of 1411 study participants, the mean age was 35.2 (6.2) years and 45.3% were male. Median plasma C-terminal FGF23 values in relative units (RU)/ml were 59.5 [interquartile range (IQR) 44.1, 85.3] in the USA, 43.2 (IQR 33.1, 57.9) in Seychelles, and 34.0 (IQR 25.2, 50.4) in Ghana. With adjustment for covariates, increasing quartiles of calcium and animal protein and decreasing quartiles of vegetable protein, fiber, and magnesium intake were associated with significantly higher FGF23 levels compared to the lowest quartile. After further adjustment for dietary factors, significant trends in FGF23 levels were noted only for quartiles of calcium, fiber, and magnesium intake (P < 0.001). Dietary factors other than phosphate are associated with FGF23 levels in young adults.

Relationships between bone mass and dietary/lifestyle habits in Japanese women at 3-4 months postpartum

OBJECTIVES

The relationships between calcaneal bone mass and dietary/lifestyle habits in women at 3-4 months postpartum were examined in the context of osteoporosis prevention.

STUDY DESIGN

Cross-sectional survey.

METHODS

We measured bone mass using calcaneal ultrasound in mothers who brought their 3- to 4-month-old babies to healthcare centers in Japan for health examination and administered a self-report questionnaire on physical characteristics and dietary/lifestyle habits to those who agreed to participate in the survey. Valid data were available for 1220 women (valid response rate, 97.5%).

RESULTS

Based on their stiffness score, a measure of bone mass, 70.9% (n = 865) of the participants were classified as 'no apparent abnormality (stiffness score ≥78.8)' (low-risk group), 18.2% (n = 222) as 'guidance required (≥70.1-<78.8)' (intermediate-risk group), and 10.9% (n = 133) as 'complete examination required (<70.1)' (high-risk group), according to the criteria for osteoporosis screening test results. The percentage of individuals with a history of fracture was higher in the guidance required/complete examination required than in the no apparent abnormality group (P = 0.016). The analysis of relationships between the consumption frequency of certain foods, such as calcium-rich foodstuffs, and bone mass found that women who reported lower frequencies of milk and dark-colored (beta-carotene rich) vegetables for breakfast consumption had a significantly lower bone mass than those who consumed these foods more often. Furthermore, the guidance required/complete examination required group had a significantly lower calcium intake than the no apparent abnormality group (P = 0.022).

CONCLUSIONS

These results indicate the need to provide postpartum women with dietary education programs to promote healthy eating habits, such as increased consumption of calcium-rich foods, and prevent osteoporosis.

Quantitative analysis of efficacy and associated factors of calcium intake on bone mineral density in postmenopausal women

A model-based meta-analysis method was performed to quantitatively analyze the efficacy characteristics of calcium intake in BMD increase among postmenopausal women. We found that age and calcium intake dose were key factors affecting the efficiency and onset of BMD change, and daily 1200 mg calcium was suggested to be a beneficial dosage.

INTRODUCTION

This paper aims to quantify the efficacy of calcium intake in preventing bone mineral density (BMD) decrease among postmenopausal women and to investigate the factors that may affect the efficacy.

METHODS

Comprehensive literature search was conducted in PubMed and EMBASE from January 2016. Placebo-controlled or no-treatment controlled randomized trials focused on calcium intake for the management of osteoporosis in postmenopausal women were included. The clinical and demographic characteristics of participants and efficacy data, defined as the mean percentage change of spine BMD (L2-L4) at each observation time point compared with that of baseline, were extracted from the studies. Model-based meta-analysis (MBMA) was used to describe the time course of BMD change by calcium intake and identify the related factors.

RESULTS

This study includes 17 trials involving 2537 subjects. The results showed that a classic pharmacodynamic maximal effect (E _max) model could describe the time course of BMD change by calcium intake. Using this model, we found that age and calcium intake dose were key factors affecting the efficiency and onset of BMD change. A 60-year-old woman administered with 800 mg/day calcium can achieve a maximum BMD increasing rate of 2.38%, and the time to reach 50% of this maximum (known as onset time) was 9.44 months. An increase of 0.0817% per year was noted in the maximal effect value for women aged between 50 and 83 years. For calcium dose interval from 250 to 2000 mg/day, the onset time was expressed as 9.44 × (dose/800)^-1.33 months. Two-year calcium intake of 700, 1200, and 2000 mg/day resulted in a maximum efficacy of BMD of 68.0, 81.3, and 89.6%, respectively. This indicates that the final efficacy had already reached the plateau (>80% E _max) under the 1200-mg/day dose.

CONCLUSION

Calcium intake can effectively postpone the tendency of BMD decrease in postmenopausal women. An increased calcium dose contributes to the shortening of the onset time. Considering the drug-acting rate and safety into account, menopausal women can be administered with a rational dose of 1200 mg/day to reduce bone loss.

Race and BMI modify associations of calcium and vitamin D intake with prostate cancer

BACKGROUND

African Americans have disproportionately higher burden of prostate cancer compared to European Americans. However, the cause of prostate cancer disparities is still unclear. Several roles have been proposed for calcium and vitamin D in prostate cancer pathogenesis and progression, but epidemiologic studies have been conducted mainly in European descent populations. Here we investigated the association of calcium and vitamin D intake with prostate cancer in multiethnic samples.

METHODS

A total of 1,657 prostate cancer patients who underwent screening and healthy controls (888 African Americans, 620 European Americans, 111 Hispanic Americans, and 38 others) from Chicago, IL and Washington, D.C. were included in this study. Calcium and vitamin D intake were evaluated using food frequency questionnaire. We performed unconditional logistic regression analyses adjusting for relevant variables.

RESULTS

In the pooled data set, high calcium intake was significantly associated with higher odds for aggressive prostate cancer (OR_{Quartile 1 vs. Quartile 4} = 1.98, 95% C.I.: 1.01-3.91), while high vitamin D intake was associated with lower odds of aggressive prostate cancer (OR_{Quartile 1 vs. Quartile 4} = 0.38, 95% C.I.: 0.18-0.79). In African Americans, the association between high calcium intake and aggressive prostate cancer was statistically significant (OR_{Quartile 1 vs. Quartile 4} = 4.28, 95% C.I.: 1.70-10.80). We also observed a strong inverse association between total vitamin D intake and prostate cancer in African Americans (OR_{Quartile 1 vs. Quartile 4} = 0.06, 95% C.I.: 0.02-0.54). In European Americas, we did not observe any significant associations between either calcium or vitamin D intake and prostate cancer. In analyses stratifying participants based on Body Mass Index (BMI), we observed a strong positive association between calcium and aggressive prostate cancer and a strong inverse association between vitamin D intake and aggressive prostate cancer among men with low BMI (<27.8 kg/m²), but not among men with high BMI (≥27.8 kg/m²). Interactions of race and BMI with vitamin D intake were significant (P _Interaction < 0.05).

CONCLUSION

Calcium intake was positively associated with aggressive prostate cancer, while vitamin D intake exhibited an inverse relationship. However, these associations varied by race/ethnicity and BMI. The findings from this study may help develop better prostate cancer prevention and management strategies.

Effects of vitamin D deficiency and daily calcium intake on bone mineral density and osteoporosis in Korean postmenopausal woman

OBJECTIVE

We evaluated the combined effects of vitamin D and daily calcium intake on bone mineral density (BMD) and osteoporosis in Korean postmenopausal women.

METHODS

This study is a cross-sectional study consisting of 1,921 Korean postmenopausal women aged 45 to 70 years without thyroid dysfunction, from the 2008-2011 Korean National Health and Nutrition Examination Survey. Participants were classified into six groups according to serum 25-hydroxyvitamin D (25(OH)D) levels and daily calcium intake. BMD was measured using dual-energy X-ray absorptiometry at femur and at lumbar spine, and the serum vitamin D levels were measured by radioimmunoassay.

RESULTS

The BMD divided according to serum 25(OH)D and daily calcium intakes were not statistically different among the groups. However, when both daily calcium intake and serum 25(OH)D were not sufficient, risk of osteopenia and osteoporosis showed significant increase in both femur neck and lumbar spine (odds ratio [OR] 2.242, P=0.006; OR 3.044, P=0.001; respectively). Although daily calcium intake was sufficient, risks of osteopenia and osteoporosis significantly increased in lumbar spine group if serum 25(OH)D is <20 ng/mL (OR 2.993, P=0.006).

CONCLUSION

The combined effects of insufficient daily calcium intake and vitamin D deficiency may cause low BMD and increase in prevalence of osteopenia and osteoporosis in Korean postmenopausal women aged 45 to 70 years.

Associations of dietary calcium intake with metabolic syndrome and bone mineral density among the Korean population: KNHANES 2008-2011

Excessive amount of calcium intake increased risk for metabolic syndrome in men. However, modest amount decreased the risk of metabolic syndrome and osteoporosis in postmenopausal women. Modest amount of calcium also increased bone mineral density (BMD) in both men and postmenopausal women.

INTRODUCTION

The present study aimed to evaluate the associations of dietary calcium intake with metabolic syndrome and bone mineral density (BMD) in Korean men and women, especially postmenopausal women.

METHODS

The study was performed using data from the Korean National Health and Nutrition Examination Survey (2008-2011) and included 14,705 participants (5953 men, 4258 premenopausal women, and 4494 postmenopausal women). Clinical and other objective characteristics, presence of metabolic syndrome, and the BMD of the femur neck and lumbar spine were evaluated according to dietary calcium intake.

RESULTS

There was a higher tendency for metabolic syndrome in men with a dietary calcium intake of >1200 mg/day than with ≤400 mg of calcium intake; >400 and ≤800 mg of calcium intake was helpful for postmenopausal women to decrease risk for metabolic syndrome. Overall, the group with calcium intake >400 and ≤800 mg daily had significantly increased BMD in both femoral neck and lumbar spine from both men and postmenopausal women. From both femoral neck and lumbar spine, the prevalence of osteoporosis in postmenopausal women significantly decreased in the group whose calcium intake was >400 and ≤800 mg daily.

CONCLUSION

Excessive dietary calcium may increase the prevalence of metabolic syndrome in men. For postmenopausal women, calcium intake does not increase the risk of metabolic syndrome, but modest amount decreases the risk. It may increase the BMD in men and postmenopausal women, and also reduce the prevalence of both osteoporosis and metabolic syndrome in postmenopausal women.

Low dairy calcium intake is associated with overweight and elevated blood pressure in Polish adults, notably in premenopausal women

OBJECTIVE

Dietary Ca is now being recognized to play an important role not only in skeletal integrity, but also in the regulation of energy and metabolism. The aim of the present study was to estimate the relationship of dairy Ca intake with BMI and blood pressure (BP) in a sample derived from the Polish population.

DESIGN

Ca intake was calculated from an interviewer-administered semi-quantitative FFQ. BMI was calculated from measured weight and height, and BP was measured by a physician.

SETTING

Cross-sectional epidemiological study on osteoporosis risk factors in Poland.

SUBJECTS

Randomly selected healthy adult persons (n 1259; 750 women and 509 men).

RESULTS

Dairy Ca intake was significantly lower in individuals with overweight/obesity (BMI≥25·00 kg/m2) and/or with elevated BP (systolic/diastolic ≥140/≥90 mmHg) than in those with normal body mass and BP, respectively. Ca intake was negatively correlated with BMI (r=-0·12, P<0·001), systolic BP (r=-0·11, P<0·001) and diastolic BP (r=-0·08, P<0·01). Daily dairy Ca intake below 1000 mg was a predictor for BMI≥25·0 kg/m2 (OR=1·44, P<0·005). This relationship was stronger in women, particularly premenopausal women.

CONCLUSIONS

The obtained results indicate the role of low dairy Ca intake in the development of obesity and hypertension, notably in premenopausal women.

The effect of prolonged breast-feeding on the development of postmenopausal osteoporosis in population with insufficient calcium intake and vitamin D level

Breast-feeding affects bone metabolism and calcium homeostasis, and prolonged breast-feeding may influence the development of postmenopausal osteoporosis, particularly in highly susceptible populations. The study determined that breast-feeding may be a risk factor for postmenopausal osteoporosis, especially in people with low calcium intakes and vitamin D deficiencies.

INTRODUCTION

The purpose of this study was to determine whether breast-feeding is a risk factor in the development of postmenopausal osteoporosis, especially in highly susceptible population.

METHODS

The study was performed using data from the 2010 to 2011 Korea National Health and Nutrition Examination Survey, and it included 1231 postmenopausal women who were aged between 45 and 70 years. Osteoporosis was defined using the World Health Organization's T-score criteria, namely, a T-score of ≤-2.5 at the femoral neck or the lumbar spine. The patients' ages, body mass indexes, daily calcium intakes, serum vitamin D levels, exercise levels, smoking histories, and reproductive factors relating to menarche, menopause, delivery, breast-feeding, hormone treatment, and oral contraceptive use were evaluated. Comparisons between the osteoporosis and non-osteoporosis groups were undertaken using Student's t test and the chi-square test, and logistic regression models were built.

RESULTS

A significant increase in the risk of osteoporosis was apparent in postmenopausal women with prolonged breast-feeding histories (≥24 months) (model 1: odds ratio [OR] = 2.489; 95 % confidence interval [CI] = 1.111 to 5.578, p = 0.027; model 2: OR = 2.503; 95 % CI = 1.118 to 5.602, p = 0.026; model 3: OR = 2.825; 95 % CI = 1.056 to 7.56, p = 0.039), particularly in those with inadequate serum vitamin D levels and calcium intakes (<800 mg/day).

CONCLUSIONS

Breast-feeding seems to increase the risk of postmenopausal osteoporosis; however, its impact may not be definitive in women with sufficient vitamin D levels and calcium intakes. Therefore, sufficient calcium intakes and adequate vitamin D levels may be important to prevent osteoporosis in postmenopausal women that is derived from breast-feeding.

Efficacy of a workplace osteoporosis prevention intervention: a cluster randomized trial

BACKGROUND

Osteoporosis is a debilitating disease. Adequate calcium consumption and physical activity are the two major modifiable risk factors. This paper describes the major outcomes and efficacy of a workplace-based targeted behaviour change intervention to improve the dietary and physical activity behaviours of working women in sedentary occupations in Singapore.

METHODS

A cluster-randomized design was used, comparing the efficacy of a tailored intervention to standard care. Workplaces were the units of randomization and intervention. Sixteen workplaces were recruited from a pool of 97, and randomly assigned to intervention and control arms (eight workplaces in each). Women meeting specified inclusion criteria were then recruited to participate. Workplaces in the intervention arm received three participatory workshops and organization-wide educational activities. Workplaces in the control/standard care arm received print resources. Outcome measures were calcium intake (milligrams/day) and physical activity level (duration: minutes/week), measured at baseline, 4 weeks and 6 months post intervention. Adjusted cluster-level analyses were conducted comparing changes in intervention versus control groups, following intention-to-treat principles and CONSORT guidelines.

RESULTS

Workplaces in the intervention group reported a significantly greater increase in calcium intake and duration of load-bearing moderate to vigorous physical activity (MVPA) compared with the standard care control group. Four weeks after intervention, the difference in adjusted mean calcium intake was 343.2 mg/day (95 % CI = 337.4 to 349.0, p < .0005) and the difference in adjusted mean load-bearing MVPA was 55.6 min/week (95 % CI = 54.5 to 56.6, p < .0005). Six months post intervention, the mean differences attenuated slightly to 290.5 mg/day (95 % CI = 285.3 to 295.7, p < .0005) and 50.9 min/week (95 % CI =49.3 to 52.6, p < .0005) respectively.

CONCLUSION

This workplace-based intervention substantially improved calcium intake and load-bearing moderate to vigorous physical activity 6 months after the intervention began.

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry ACTRN12616000079448 . Registered 25 January 2016 (retrospectively registered).

The Association between Coffee Consumption and Bone Status in Young Adult Males according to Calcium Intake Level

The purpose of this study was to investigate the association between coffee consumption and bone status (bone mineral density and bone metabolism-related markers) according to calcium intake level in Korean young adult males. Healthy and nonsmoking males (19-26 years, n = 330) participated in this study. Anthropometric measurements, dietary habits, and nutrient intakes were surveyed. Bone status of the calcaneus was measured by using quantitative ultrasound (QUS). Bone metabolism-related markers including serum total alkaline phosphatase activity (TALP), N-mid osteocalcin (OC), and type 1 collagen C-terminal telopeptide (1CTP) were analyzed. The subjects were divided into two groups based on daily calcium intake level: a calcium-sufficient group (calcium intake ≥ 75% RI, n = 171) and a calcium-deficient group (calcium intake < 75% RI, n = 159). Each group was then further divided into three subgroups based on daily average coffee consumption: no-coffee, less than one serving of coffee per day, and one or more servings of coffee per day. There were no significant differences in height, body weight, body mass index, energy intake, or calcium intake among the three coffee consumption subgroups. QUS parameters and serum 1CTP, TALP, and OC were not significantly different among either the two calcium-intake groups or the three coffee consumption subgroups. Our results may show that current coffee consumption level in Korean young men is not significantly associated with their bone status and metabolism according to the calcium intake level.

Reducing Iron Deficiency in 18-36-months-old US Children: Is the Solution Less Calcium?

Objectives National surveys consistently identify iron deficiency (ID) in US children between 1 and 3 years of age, when the brain is rapidly developing and vulnerable to the effects of ID. However, controversy remains as to how best to recognize and prevent ID in young children, in part because of the multiple potential etiologies. The objective of this project was to assess ID in children and identify potential individual dietary predictors of status. Methods We examined three biomarkers of ID [soluble transferrin receptor (sTfR) and serum ferritin (SF), and body iron (calculated from sTfR and SF)] against parent-provided dietary calcium and iron intake for eight-three 18-36 month old children from middle class families. Results Using literature-based cutoffs, fourteen children (16.9 %) had at least one indicator of ID: low SF(<10 μg/l, 7.2 %), negative body iron (<0 mg/kg, 7.2 %) or elevated sTfR (>8.4 μg/ml, 13.2 %). All children consumed more than the Dietary Reference Intake (DRI) Estimated Average Requirement of 3 mg/d iron. The mean iron intake of children identified with ID approximated the Recommended Dietary Allowance of 7 mg/d. Most children (81 %) consumed above the DRI Adequate Intake of 500 mg/d of calcium. Calcium intakes were generally high and predicted lower body iron (p = 0.0005), lower SF (p = 0.0086) and higher sTfR (p = 0.0176). Conclusions for Practice We found rates of ID similar to US national averages. Dietary calcium intake predicted lower iron status more than deficits in iron intake. Teaching parents to balance calcium and iron intake in toddlers could be a strategy to prevent ID.

A Cross-Sectional Study of the Association of VDR Gene, Calcium Intake, and Heel Ultrasound Measures in Early Adulthood

The acquisition of a high adult peak bone mass (PBM) is considered an important determinant of osteoporotic risk later in life. Genetic and environmental factors determine optimal PBM acquisition in early adulthood. The aim of this study was to test the association of vitamin D receptor (VDR) gene polymorphisms and dietary calcium intake with the bone mass of young adults. The study population comprised a total of 305 individuals (mean age 20.41; SD 2.36) whose bone mass was assessed through heel ultrasound [quantitative ultrasound measurements (QUS)] measurements (BUA, dB/MHz). The FokI G/A, rs9729 G/T, and TaqI G/A polymorphisms were selected as genetic markers of VDR. A significant difference in BUA values was observed according to gender (females 82.96; SD 15.89 vs. males 97.72; SD 16.50; p < 0.00001). The mean dietary calcium intake of the study group (827.84 mg/day; SD 347.04) was lower than the dietary reference intake for young adults (1000 mg/day) and had no association with BUA. None of the three VDR polymorphisms tested showed an association with BUA. Similarly, the analysis of VDR 3' haplotypes, estimated using rs9729 and Taq1 as tag SNPs, did not reveal any significant association with QUS traits. Our results confirm the existence of different heel QUS for women and men, as well as a tendency towards low calcium consumption by young adults, and they also suggest that the VDR gene does not play a major role in the genetic determination of QUS parameter in early adulthood.

Dietary recommendations and treatment of patients with recurrent idiopathic calcium stone disease

This review describes the various dietary regimens that have been used to advise patients on how to prevent the recurrence of their calcium-containing kidney stones. The conclusion is that although there is some general advice that may be useful to many patients, it is more efficacious to screen each patient individually to identify his/her main urinary, metabolic, nutritional, environmental, and lifestyle risk factors for stone-formation and then tailor specific advice for that particular patient based on the findings from these investigations. If the patient can be motivated to adhere strictly to this conservative approach to the prophylactic management of their stone problem over a long time period, then it is possible to prevent them from forming further stones. This approach to stone management is considerably less expensive than any of the procedures currently available for stone removal or disintegration. In the UK, for each new stone episode prevented by this conservative approach to prophylaxis it is calculated to save the Health Authority concerned around £2000 for every patient treated successfully. In the long term, this accumulates to a major saving within each hospital budget if most stone patients can be prevented from forming further stones and when the savings are totalled up country-wide saves the National Exchequer considerable sums in unclaimed Sick Pay and industry a significant number of manpower days which would otherwise be lost from work. It is also of immense relief and benefit to the patients not to have to suffer the discomfort and inconvenience of further stone episodes.

Calcium intake, polymorphisms of the calcium-sensing receptor, and recurrent/aggressive prostate cancer

PURPOSE

To assess whether calcium intake and common genetic variants of the calcium-sensing receptor (CASR) are associated with either aggressive prostate cancer (PCa) or disease recurrence after prostatectomy.

METHODS

Calcium intake at diagnosis was assessed, and 65 common single-nucleotide polymorphisms (SNPs) in CASR were genotyped in 886 prostatectomy patients. We investigated the association between calcium intake and CASR variants with both PCa recurrence and aggressiveness (defined as Gleason score ≥4 + 3, stage ≥pT3, or nodal-positive disease).

RESULTS

A total of 285 men had aggressive disease and 91 experienced recurrence. A U-shaped relationship between calcium intake and both disease recurrence and aggressiveness was observed. Compared to the middle quintile, the HR for disease recurrence was 3.07 (95% CI 1.41-6.69) for the lowest quintile and 3.21 (95% CI 1.47-7.00) and 2.97 (95% CI 1.37-6.45) for the two upper quintiles, respectively. Compared to the middle quintile, the OR for aggressive disease was 1.80 (95% CI 1.11-2.91) for the lowest quintile and 1.75 (95% CI 1.08-2.85) for the highest quintile of calcium intake. The main effects of CASR variants were not associated with PCa recurrence or aggressiveness. In the subgroup of patients with moderate calcium intake, 31 SNPs in four distinct blocks of high linkage disequilibrium were associated with PCa recurrence.

CONCLUSIONS

We observed a protective effect of moderate calcium intake for PCa aggressiveness and recurrence. While CASR variants were not associated with these outcomes in the entire cohort, they may be associated with disease recurrence in men with moderate calcium intakes.