Dietary caffeine intake and bone status of postmenopausal women

Causal association of genetically determined caffeine intake from tea or coffee with bone health: a two-sample Mendelian randomization study

BACKGROUND

Relationship of caffeine intake and consumption of caffeinated beverages, such as tea and coffee, with bone health remains controversial. This study aimed to evaluate whether genetically determined caffeine intake from tea or coffee has causal effects on overall total body bone mineral density (TB-BMD) and fracture. We also assessed the association with TB-BMD in five age strata.

METHODS

Using two-sample Mendelian randomization approach, summary statistics were retrieved from genome-wide association studies (GWAS)/GWAS meta-analyses of caffeine intake from tea (n = 395 866)/coffee (n = 373 522), TB-BMD (n = 66 628), and fracture (n = 426 795). Inverse variance weighted method was adopted as the main univariable analysis. Multivariable analysis was conducted to evaluate whether the causal effect is independent.

RESULTS

In univariable analysis, genetically determined caffeine intake from tea had positive association with overall TB-BMD (per SD increase in genetically determined caffeine intake, beta of TB-BMD [in SD]: 0.166; 95% confidence interval (CI): 0.006-0.326) and inverse association with fracture (OR = 0.79; 95% CI: 0.654-0.954). Genetically determined caffeine intake from coffee was also positively associated with overall TB-BMD (beta = 0.231; 95% CI: 0.093-0.369). The association remained significant after adjustment for smoking in multivariable analysis. Genetically determined caffeine intake from tea or coffee was both positively associated with TB-BMD in the age strata of 45-60 years, but we lacked evidence of association in other strata.

CONCLUSIONS

Genetically, caffeine intake from tea or coffee may be beneficial to bone health. Due to the ascertainment method of caffeine intake from tea, our study also implied genetically higher tea consumption may improve TB-BMD and lower fracture risk.

Role of lifestyle factors in mediating the effect of educational attainment on bone mineral density: a Mendelian randomization study

We performed two-step multivariable Mendelian randomization analysis to explore the mediating role of lifestyle factors in educational attainment (EA) and bone mineral density (BMD). Summary statistics from genome-wide association studies of European lineages were used. Coffee intake and processed-meat intake mediated the association between EA and BMD.

PURPOSE

This study aimed to explore the causal relationship between educational attainment (EA) and bone mineral density (BMD), as well as the potential mediating roles of lifestyle factors in the expected EA-BMD relationship. By identifying modifiable lifestyle factors, we hope to provide relevant information to prevent osteoporosis or low BMD in the less educated population.

METHODS

Using summary statistics from genome-wide association studies (GWAS) of major European lineages, one- and two-sample Mendelian randomization (MR) analyses were performed to estimate the association between EA (in the social sciences genetic association consortium (SSGAC) involving 766,345 individuals and in the UK Biobank (UKB) involving 293,723 individuals) and BMD (in the Genetic Factors for Osteoporosis Consortium involving 426,824 individuals selected from the UKB). The EA variable in both consortia were expressed by years of schooling completed. Two-step multivariable MR was used to assess the mediating roles of eight lifestyle-related factors (moderate-to-vigorous physical activity, watching television, computer using, smoking initiation, coffee intake, alcohol intake frequency, tea intake, and processed-meat intake) in the EA and BMD association, and the corresponding mediating proportion was calculated. Meta-analysis was used to present a pooled estimate.

RESULTS

A total of 317 and 73 independent single-nucleotide polymorphisms (SNPs) of GWAS significance (P < 5.0 × 10-8) were selected as instrumental variables (IVs) for EA in the SSGAC and UKB, respectively. A total of 513 SNPs were selected as IVs for the BMD. The results of one- and two-sample MR revealed that the genetically predicted BMD increased by 0.094 and 0.047 g/cm2, respectively, in response to each SD increment of genetically predicted schooling years. Among the eight candidate mediators, coffee intake and processed-meat intake were potential mediators revealed by the two-step multivariable MR analysis, mediating 26.87% and 23.92% of EA's effect on BMD, respectively. Meta-analysis showed consistent findings. Results of sensitivity analysis indicated the robustness of our findings.

CONCLUSION

We elucidated the causal protective effect of EA on BMD and the mediating roles of coffee intake and processed-meat intake. Intervening with these factors can potentially reduce the burden of bone density loss or osteoporotic fractures among the less educated population.

Association of Coffee and Tea Intake with Bone Mineral Density and Hip Fracture: A Meta-Analysis

Background and Objectives: Osteoporosis is characterized by low bone mass and high bone fragility. Findings regarding the association of coffee and tea intake with osteoporosis have been inconsistent. We conducted this meta-analysis to investigate whether coffee and tea intake is associated with low bone mineral density (BMD) and high hip fracture risk. Materials and Methods: PubMed, MEDLINE, and Embase were searched for relevant studies published before 2022. Studies on the effects of coffee/tea intake on hip fracture/BMD were included in our meta-analysis, whereas those focusing on specific disease groups and those with no relevant coffee/tea intake data were excluded. We assessed mean difference (MD; for BMD) and pooled hazard ratio (HR; for hip fracture) values with 95% confidence interval (CI) values. The cohort was divided into high- and low-intake groups considering the thresholds of 1 and 2 cups/day for tea and coffee, respectively. Results: Our meta-analysis included 20 studies comprising 508,312 individuals. The pooled MD was 0.020 for coffee (95% CI, -0.003 to 0.044) and 0.039 for tea (95% CI, -0.012 to 0.09), whereas the pooled HR was 1.008 for coffee (95% CI, 0.760 to 1.337) and 0.93 for tea (95% CI, 0.84 to 1.03). Conclusions: Our meta-analysis results suggest that daily coffee or tea consumption is not associated with BMD or hip fracture risk.

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.

Effects of cigarette smoke inhalation and coffee consumption on bone formation and osseous integration of hydroxyapatite implant

The present study aims to assess the effects of cigarette smoke inhalation and/or coffee consumption on bone formation and osseous integration of a dense hydroxyapatite (DHA) implant in rats. For this study, 20 male rats were divided into four groups (n = 5): CT (control) group, CE (coffee) group, CI (cigarette) group and CC (coffee + cigarette) group. During 16 weeks, animals in the CI group were exposed to cigarette smoke inhalation equivalent to 6 cigarettes per day; specimens in the CE group drank coffee as liquid diet; and rats in the CC group were submitted to both substances. In the 6th week a 5 mm slit in the parietal bone and a 4 mm slit in the tibia were performed on the left side: the former was left open while the latter received a DHA implant. As soon as surgeries were finished, the animals returned to their original protocols and after 10 weeks of exposure they were euthanised (ethically sacrificed) and the mentioned bones collected for histological processing. Data showed that exposure to cigarette smoke inhalation and coffee consumption did not interfere in weight gain and that solid and liquid diet consumption was satisfactory. Rats in the CC group showed a decrease in bone neoformation around the tibial DHA implant (31.8 ± 2.8) as well as in bone formation in the parietal slit (28.6 ± 2.2). On their own, cigarette smoke inhalation or coffee consumption also led to diminished bone neoformation around the implant and delayed the bone repair process in relation to the CT group. However, reduction in the bone repair process was accentuated with exposure to both cigarette smoke inhalation and coffee consumption in this study.

Caffeine regulates osteogenic differentiation and mineralization of primary adipose-derived stem cells and a bone marrow stromal cell line

Caffeine consumption reportedly influences bone mineral density and body weight. However, the effects of caffeine on bone metabolism are still controversial, and whether the dosage of caffeine influences osteogenic differentiation is yet to be clarified. In the present study, we cultured primary adipose-derived stem cells (ADSCs) and a bone marrow stromal cell line (M2-10B4) in osteogenic differentiation media containing varying concentrations of caffeine. Caffeine had biphasic effects: 0.1 mM caffeine significantly enhanced mineralization and alkaline phosphatase (ALP) activity. Consistent with these observations, a caffeine concentration of 0.1 mM upregulated the osteogenic differentiation marker genes ALP and osteocalcin (OCN), and elevated osteoprotegerin (OPG), Runt-related transcription factor 2 (RUNX2) and Sirtuin 1 (SIRT1) levels. However, a concentration of caffeine greater than 0.3 mM suppressed the differentiation of both the cell types. These findings indicate that caffeine has a beneficial effect on ADSCs and bone marrow stromal cells, enhancing differentiation to osteoblasts; this effect, which is mediated via RUNX2 activation at low doses is significantly suppressed at high doses.

Bone mineral density, polyphenols and caffeine: a reassessment

Several studies have shown beneficial associations between tea consumption and bone mineral density (BMD) and fracture risk. Current investigations into potential mechanisms of benefit are focused upon the F and polyphenol components of tea. However, previous studies have pointed towards caffeine consumption as a potential risk factor for low BMD and high fracture risk. Tea, therefore, represents an interesting paradox as a mildly caffeinated beverage that may enhance bone health. Fruit and vegetable intake has also been associated with BMD, and it is now apparent that several fruit and vegetable components, including polyphenols, may contribute positively to bone health. Evidence surrounding the function(s) of polyphenol-rich foods in bone health is examined, along with more recent studies challenging the relevance of caffeine consumption to in vivo Ca balance. Plant foods rich in polyphenols such as tea, fruit and vegetables, as significant factors in a healthy diet and lifestyle, may have positive roles in bone health, and the negative role of caffeine may have been overestimated. The present review covers evidence of dietary mediation in positive and negative aspects of bone health, in particular the roles of tea, fruit and vegetables, and of caffeine, flavonoids and polyphenols as components of these foods. Since the deleterious effects of caffeine appear to have been overstated, especially in respect of the positive effects of flavonoids, it is concluded that a reassessment of the role of caffeinated beverages may be necessary.

Predictors of bone mineral density in a convenience sample of young Caucasian adults living in southern Ontario

Osteoporosis is a major public health concern in Canada and worldwide. Although much is known about bone health in older adults, little is known about bone health in young, healthy Canadian men and women. The objectives of this research were to describe bone mineral density (BMD) of young, healthy adults living in southern Ontario, Canada, and to identify predictors of BMD in this population. Two-hundred and fifty-eight Caucasian men and women aged 18–33 years completed health and physical activity questionnaires along with a calcium and vitamin D specific food frequency questionnaire. Height and mass were measured. BMD of the total hip, femoral neck, spine, and total body was measured using dual energy X-ray absorptiometry. Among men, body mass, weight-bearing physical activity, and calcium intake were significant predictors of BMD. Among women, body mass, calcium intake, and family history of osteoporosis significantly predicted log BMD. The predictors of BMD in young Canadian men and women identified in this study may inform the development of longitudinal studies designed to examine the influence of lifestyle factors on BMD in young adults.

Coffee consumption and CYP1A2 genotype in relation to bone mineral density of the proximal femur in elderly men and women: a cohort study

Background

Drinking coffee has been linked to reduced calcium conservation, but it is less clear whether it leads to sustained bone mineral loss and if individual predisposition for caffeine metabolism might be important in this context. Therefore, the relation between consumption of coffee and bone mineral density (BMD) at the proximal femur in men and women was studied, taking into account, for the first time, genotypes for cytochrome P450 1A2 (CYP1A2) associated with metabolism of caffeine.

Methods

Dietary intakes of 359 men and 358 women (aged 72 years), participants of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), were assessed by a 7-day food diary. Two years later, BMD for total proximal femur, femoral neck and trochanteric regions of the proximal femur were measured by Dual-energy X-ray absorptiometry (DXA). Genotypes of CYP1A2 were determined. Adjusted means of BMD for each category of coffee consumption were calculated.

Results

Men consuming 4 cups of coffee or more per day had 4% lower BMD at the proximal femur (p = 0.04) compared with low or non-consumers of coffee. This difference was not observed in women. In high consumers of coffee, those with rapid metabolism of caffeine (C/C genotype) had lower BMD at the femoral neck (p = 0.01) and at the trochanter (p = 0.03) than slow metabolizers (T/T and C/T genotypes). Calcium intake did not modify the relation between coffee and BMD.

Conclusion

High consumption of coffee seems to contribute to a reduction in BMD of the proximal femur in elderly men, but not in women. BMD was lower in high consumers of coffee with rapid metabolism of caffeine, suggesting that rapid metabolizers of caffeine may constitute a risk group for bone loss induced by coffee.

Caffeine's implications for women's health and survey of obstetrician-gynecologists' caffeine knowledge and assessment practices

OBJECTIVE

Caffeine has relevance for women's health and pregnancy, including significant associations with spontaneous abortion and low birth weight. According to scientific data, pregnant women and women of reproductive age should be advised to limit their caffeine consumption. This article reviews the implications of caffeine for women's psychological and physical health, and presents data on obstetrician-gynecologists' (ob-gyns) knowledge and practices pertaining to caffeine.

METHODS

Ob-gyns (N = 386) who are members of the American College of Obstetricians and Gynecologists' Collaborative Ambulatory Research Network responded to a 21-item survey about caffeine.

RESULTS

Although most knew that caffeine is passed through breast milk, only 24.8% were aware that caffeine metabolism significantly slows as pregnancy progresses. Many respondents were not aware of the caffeine content of commonly used products, such as espresso and Diet Coke, with 14.3% and 57.8% indicating amounts within an accurate range, respectively. Furthermore, ob-gyns did not take into account large differences in caffeine content across different caffeinated beverages with most recommending one to two servings of coffee or tea or soft drinks per day. There was substantial inconsistency in what was considered to be "high levels" of maternal caffeine consumption, with only 31.6% providing a response. When asked to indicate the risk that high levels of caffeine have on various pregnancy outcomes, responses were not consistent with scientific data. For example, respondents overestimated the relative risk of stillbirths and underestimated the relative risk of spontaneous abortion. There was great variability in assessment and advice practices pertaining to caffeine. More than half advise their pregnant patients to consume caffeine under certain circumstances, most commonly to alleviate headache and caffeine withdrawal.

CONCLUSIONS

The data suggest that ob-gyns could benefit from information about caffeine and its relevance to their clinical practice. The development of clinical practice guidelines for caffeine may prove to be useful.

Chronic obstructive pulmonary disease is associated with osteoporosis and low levels of vitamin D

We did a cross-sectional analysis of chronic pulmonary obstructive disease (COPD) patients without chronic use of systemic glucocorticoids (CUG). Osteoporosis was found in 51% and bone mineral density (BMD) was correlated with severity of disease. Low levels of vitamin D were found in 94%. All COPD patients may benefit from vitamin D supplementation and screening for low BMD.

INTRODUCTION

Patients with chronic pulmonary obstructive disease have low bone mineral density, caused by chronic use of systemic glucocorticoids and hypovitaminosis D. However, patients without CUG may also have low BMD.

METHODS

We performed a cross-sectional analysis in 49 patients (21 men, 28 postmenopausal women), with COPD without CUG, from Brazil (25 degrees 25' S). Several markers of bone metabolism were measured, plus BMD. Osteoporosis risk factors and history of fractures were investigated. Respiratory function was assessed by venous gasometry, spirometry, and oximetry. BMD results were compared to those of 40 healthy non-smokers controls.

RESULTS

COPD patients had lower BMD at all sites (p < 0.01). Osteoporosis was observed in 51%. BMD independently correlated with stage of disease (lumbar spine, R = 0.38, p = 0.01; total femur, R = 0.36, p = 0.01; femoral neck, R = 0.40, p < 0.01). Ninety-four percent had low levels of vitamin D (<30 ng/mL) and 67% had secondary hyperparathyroidism. Vitamin D was correlated with oxygen saturation (R = 0.36, p = 0.01), with lower levels in those with saturation <88% (p = 0.01).

CONCLUSION

Patients with COPD without CUG have increased risk for osteoporosis. Such patients have hypovitaminosis D, which is correlated with the severity of disease. Screening for low BMD and vitamin D supplementation may be warranted to all COPD patients.

Prevalence of osteoporosis in community-dwelling individuals with intellectual and/or developmental disabilities

OBJECTIVE

Measure central bone mineral density (BMD) in community-dwelling individuals with intellectual and/or developmental disabilities.

DESIGN

A cross-sectional study.

SETTING

A regional center providing outpatient medical, residential, and day activity services for individuals with intellectual and/or developmental disabilities.

PARTICIPANTS

Documented BMD results were obtained for 298 community-dwelling individuals with intellectual and/or developmental disabilities.

MEASUREMENTS

BMD by central dual-energy x-ray absorptiometry (DXA) on the participant's spine, converted into T-scores categories using CDC guidelines (T < or = -2.5 [osteoporotic]; -2.5 > T < -1.0 [osteopenic]; > or = -1.0 [normal]). Comparisons were made using multiple regression to determine significant independent risk factors for low BMD.

RESULTS

Significant predictors were noted in the rates of osteoporosis attributable to subject age, race, and level of ambulation. No gender differences were noted for the rate of osteoporosis in this community sample of individuals with intellectual and/or developmental disabilities, nor were any differences noted for varying levels of mental retardation. Diagnostic differences were significant only for those individuals with a diagnosis of metabolic error, who had a significantly lower rate of osteoporosis than the rest of the study population.

CONCLUSION

This study's findings regarding age, race, and level of ambulation are consistent with those of previous studies using an intellectually and/or developmentally disabled population as well as the general population at large. Our finding that the rate of osteoporosis among disabled males is higher than for males in the general population suggests a possible case-finding deficit for asymptomatic males in the general population. It is also interesting that the only diagnostic category observed to be statistically different from the group in general was metabolic error, a finding that warrants further investigation.

Association between caffeine intake and bone mass among young women: potential effect modification by depot medroxyprogesterone acetate use

This study assessed associations between habitual caffeine intake and bone mass among young women. Analyses of the entire study population revealed no significant associations, while analyses restricted to women using depot medroxyprogesterone acetate (DMPA) showed modest inverse associations between caffeine intake and bone mineral content (BMC).

INTRODUCTION

Some previous investigations among postmenopausal women suggest an inverse relationship between caffeine intake and bone mass, yet studies of this association among young women are few.

METHODS

The association between habitual caffeine intake and bone mass was evaluated prospectively in a population-based cohort of 625 females, aged 14 to 40 years, adjusting for relevant biological and lifestyle factors. Caffeinated beverage intake was self-reported, and bone mineral content (BMC) and bone mineral density (BMD) were measured at baseline and every 6 months throughout a 24-month follow-up period using dual-energy x-ray absorptiometry.

RESULTS

Cross-sectional analyses revealed no significant differences in mean BMC or BMD at baseline. Mean percentage and absolute changes in BMC and BMD were not associated with caffeine use. Repeated measures analyses similarly showed no significant association between caffeine intake at baseline and mean BMC or BMD measured during follow-up. However, among women using depot medroxyprogesterone acetate (DMPA), modest inverse associations between caffeine and BMC (but not BMD) were detected.

CONCLUSIONS

Our data suggest that heavy habitual consumption of caffeinated beverages does not adversely impact bone mass among young women in general. Greater caffeine intake may be associated with lower BMC among DMPA users.

Patient assessment in the diagnosis, prevention, and treatment of osteoporosis

Assessment of the patient with osteoporosis includes history and physical examination, laboratory testing, and imaging studies. Information gathered during this assessment assists clinicians in targeting strategies to prevent fractures. The medical history should contain items such as personal and family history of fractures, lifestyle, intake of substances such as vitamin D, calcium, corticosteroids, and other medications. The physical examination can reveal relevant information such as height loss and risk of falls. Bone mineral density (BMD), most commonly determined by dual-energy x-ray absorptiometry, best predicts fracture risk in patients without previous fracture. BMD testing is most efficient in women over 65 years old but is also helpful for men and women with risk factors. Serial BMD tests can identify individuals losing bone mass, but clinicians should be aware of what constitutes a significant change. Laboratory testing can detect other risk factors and can provide clues to etiology. Selection of laboratory tests should be individualized, as there is no consensus regarding which tests are optimal. Biochemical markers of bone turnover have a potential role in fracture risk assessment and in gauging response to therapy, but are not widely used at present. Clinicians should be aware of problems with vitamin D measurement, including seasonal variation, variability among laboratories, and the desirable therapeutic range. Careful assessment of the osteoporotic patient is essential in developing a comprehensive plan that reduces fracture risk and improves quality of life.

Direct effects of caffeine on osteoblastic cells metabolism: the possible causal effect of caffeine on the formation of osteoporosis

BACKGROUND

Caffeine consumption has been reported to decrease bone mineral density (BMD), increase the risk of hip fracture, and negatively influence calcium retention. In this study, we investigated the influence of caffeine on the osteoblasts behaviour.

METHOD

Osteoblasts derived from newborn Wistar-rat calvaria was used in this study. The effects of various concentrations of caffeine on bone cell activities were evaluated by using MTT assay. Alkaline phosphatase (ALP) staining, von Kossa staining and biochemical parameters including ALP, lactate dehydrogenase (LDH), prostaglandin E2 (PGE2) and total protein were performed at day 1, 3, and 7. DNA degradation analysis under the caffeine influence was also performed.

RESULTS AND DISCUSSION

The results showed that the viability of the osteoblasts, the formation of ALP positive staining colonies and mineralization nodules formation in the osteoblasts cultures decreased significantly in the presence of 10 mM caffeine. The intracellular LDH, ALP and PGE2 content decreased significantly, the LDH and PGE2 secreted into the medium increased significantly. The activation of an irreversible commitment to cell death by caffeine was clearly demonstrated by DNA ladder staining.

CONCLUSION

In summary, our results suggest that caffeine has potential deleterious effect on the osteoblasts viability, which may enhance the rate of osteoblasts apoptosis.

Caffeine-mediated enhancement of glucocorticoid receptor activity in human osteoblastic cells

Caffeine-containing beverage consumption has been reported to be associated with an increased risk for osteoporosis. Since the glucocorticoid receptor (GR) is a major factor in the induction of osteoporosis we analyzed whether caffeine may act via altering GR function. Applying a reporter gene assay we provide evidence that caffeine drastically amplifies GR transcriptional activity in human osteoblastic cells. Substances that increase the intracellular cyclic AMP-concentration also strengthen the transactivity of the GR and coincubation with caffeine further reinforces this potentiation, indicating that caffeine-mediated enhancement of GR transcriptional function is due to the inhibitory activity of caffeine on the cyclic AMP phosphodiesterase. Our data suggest evidence for a hitherto unrecognized crosstalk between caffeine-modulated signalling and GR-initiated gene expression in human osteoblastic cells and could provide the molecular basis for the role of caffeine in osteoporosis.

Bone mineral density and serum levels of 25 OH vitamin D in chronic users of antiepileptic drugs

The aim of this cross sectional study was to evaluate bone mineral density (BMD) and serum levels of 25-hydroxy vitamin D (25OHD) in a group of patients taking antiepileptic drugs (AED) for a seizure disorder. Between May-2001 and January-2003, we evaluated 58 patients (40 women/18 men), 34.4+/-6 years old living in Curitiba or in its metropolitan area, on antiepileptic therapy for 2 to 38 years (10 on monotherapy /48 on multiple drugs regime). The group was matched by age, gender, and bone mass index to 29 healthy subjects (20 women/ 9 men); 34.2+/-5.9 years old. Medical history and physical exam were performed on all subjects with particular information sought about fractures and risks factors for osteoporosis. Blood samples were collected for total serum calcium, albumin, phosphorus, creatinine, total alkaline phosphatase, and liver function tests. BMD of the lumbar spine, femur and forearm was determined by dual energy X-ray absorptiometry (DXA, Hologic QDR 1000). Between February and April-2003, other blood samples were collected to measure 25OHD, intact paratohormone (PTH) and calcium. Unemployment and smoking history were more frequent among patients than among controls (p<0.05). Fifteen patients had a fracture history, all of which occurred during a seizure. The BMD of the lumbar spine (0.975+/-0. 13 g/cm2 vs. 1.058+/-0.1 g/cm2; p<0.03) and of the total femur (0.930+/-0.1 g/cm2 vs. 0.988+/-0.12 g/cm2; p<0.02) was lower in patients than in controls. In 63.5% of patients and in 24.1 % of controls a T-score < -1.0 in at least one site was seen. The AED users had higher total alkaline phosphatase and lower 25OHD (p<0.02). No correlations between BMD and 25OHD were found. The use of phenytoin was correlated with a greater incidence of fractures (RR: 2.38). We conclude that patients on chronic use of AED have alterations in bone metabolism characterized in this study by lower BMD of the lumbar spine and total femur and lower serum concentrations of 25OHD.

Osteoporose em mulheres na pós-menopausa, cálcio dietético e outros fatores de risco

O objetivo deste trabalho foi examinar os principais fatores de risco associados ao desenvolvimento de osteoporose primária em mulheres na pós-menopausa com osteopenia. Setenta e seis pacientes entre 46 e 85 anos foram selecionadas; 56,6% apresentaram diagnóstico de osteopenia e 43,4%, de osteoporose, de acordo com o critério da Organização Mundial da Saúde. Os fatores de risco foram pesquisados por meio de registro clínico e questionário de freqüência alimentar. O odds ratio foi calculado por meio do aplicativo Statistica. Oitenta e seis por cento das mulheres com osteopenia e 84,8% das com osteoporose apresentaram baixa ingestão de cálcio através de produtos lácteos. O teste "t" para amostras independentes foi aplicado e não inferiu diferença significativa (p= 0,99) entre os dois grupos. No grupo com osteopenia, os fatores de risco assumiram a seguinte forma hierárquica: ausência de terapia de reposição hormonal (2,000), não-exposição ao sol (1,516), consumo de bebidas alcoólicas na juventude (1,346), consumo atual inadequado de cálcio (1,163), ausência de atividade física atual (1,145), história familiar de osteoporose (1,101), ausência de atividade física na juventude (1,006), tabagismo (0,851) e consumo atual de bebidas alcoólicas (0,827). Em conclusão, a ausência de terapia de reposição hormonal foi o fator de risco que indicou maior probabilidade de ocorrência de osteoporose entre as mulheres com osteopenia.

Use of oral contraceptives blunts the calciuric effect of caffeine in young adult women

Caffeine consumption increases the urinary excretion of calcium and other minerals. Factors that affect caffeine metabolism such as steroid hormones may modify this effect. The purpose of this study was to evaluate the influence of oral contraceptive (OC) use on the 4-h urinary excretion of calcium, phosphorus, magnesium, zinc, sodium, potassium and caffeine metabolites in response to a high caffeine dose given as coffee beverage. Adult women, 20-29 y, users (+OC, n = 15) and nonusers (-OC, n = 15) of oral contraceptives, with calcium intake approximately 500 mg/d, participated in two tests, caffeine load (5 mg/kg body weight) and no-caffeine control, in a randomized crossover design. The net increase (caffeine load corrected by no caffeine) in urinary excretion of most minerals was significantly higher in -OC than in +OC (P < 0.05), with the larger group difference for calcium (ninefold) followed by magnesium (twofold), zinc (onefold) and potassium (onefold). Net increases in urinary excretion of 1-methylurate and paraxanthine were about three- and fivefold higher, respectively, in -OC than in +OC (P < 0.05) whereas net increases in urinary excretion of 5-acetylamino-6-formylamino-3-methyluracil (AFMU) and 1,7-dimethylurate were over twofold higher in the +OC than in -OC (P < 0.05). Following the caffeine load, most urinary minerals showed negative correlation with urinary 1-methylurate in -OC (R </= -0.78, P < 0.01), and with urinary AFMU and 1,7-dimethylurate in +OC (R </= -0.84, P < 0.01). Oral contraceptives appear to limit the renal effect of caffeine on mineral excretion possibly by reducing paraxanthine excretion, the most active caffeine metabolite.

Effects of caffeine on human health

Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks), in products containing cocoa or chocolate, and in medications. Because of its wide consumption at different levels by most segments of the population, the public and the scientific community have expressed interest in the potential for caffeine to produce adverse effects on human health. The possibility that caffeine ingestion adversely affects human health was investigated based on reviews of (primarily) published human studies obtained through a comprehensive literature search. Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day(-1) (equivalent to 6 mg kg(-1) body weight day(-1) in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility. The data also show that reproductive-aged women and children are 'at risk' subgroups who may require specific advice on moderating their caffeine intake. Based on available evidence, it is suggested that reproductive-aged women should consume </=300 mg caffeine per day (equivalent to 4.6 mg kg(-1) bw day(-1) for a 65-kg person) while children should consume </=2.5 mg kg(-1) bw day(-1).

To drink or not to drink: how are alcohol, caffeine and past smoking related to bone mineral density in elderly women?

OBJECTIVES

To determine relationship between alcohol, caffeine, past smoking and bone mineral density of different skeletal sites in elderly women, accounting for other biological and life-style variables.

METHODS/DESIGN

A cross-sectional study in 136 Caucasian women, mean +/- SD age 68.6 +/- 7.1 years, all healthy and free of medications affecting bones, including estrogen. Bone mineral density (BMD) of multiple skeletal regions and body composition were measured by dual X-ray absorptiometry. Serum vitamin D (25-OHD) and parathyroid hormone (PTH) were analyzed and used as confounders. Calcium (Ca) intake was assessed by food frequency questionnaire. Alcohol and caffeine consumption was assessed by questionnaires determining frequency, amount and source of each. There were no current smokers, but the history of smoking was recorded, including number of years and packages smoked/day. Past physical activity was assessed by Allied Dunbar National Fitness Survey and used as confounder. Statistical significance was considered at p <or= 0.05.

RESULTS

In the correlational analysis, alcohol was positively associated with spine BMD (r = 0.197, p = 0.02), 25-OHD and negatively with PTH. Smoking was negatively related to Ca intake, 25(OH)D and number of reproductive years. In subgroup (stratified by Ca intake) and multiple regression analyses, alcohol (average approximately 0.5-1 drinks/day or approximately 8 g alcohol/day) was favorably associated with BMD of spine and total body. Caffeine (average approximately 2.5 6-fl oz cups/day or 200-300 mg caffeine/day) had negative association with most of the skeletal sites, which was attenuated with higher Ca intake (>or=median, 750 mg/day). The past smokers who smoked on average 24 years of approximately 1 pack cigarettes/day had lower BMD in total body, spine and femur than never-smokers when evaluated in subgroup analyses, and the association was attenuated in participants with >or=median Ca intake. There was no significant association between past smoking and BMD of any skeletal site in multiple regression analyses.

CONCLUSION

The results support the notion that consumption of small/moderate amount of alcohol is positively, while caffeine and past smoking are negatively associated with most of the skeletal sites, which might be attenuated with Ca intake above 750 mg/day.

Effects of caffeine on bone and the calcium economy

Caffeine-containing beverage consumption has been reported to be associated with reduced bone mass and increased fracture risk in some, but not most, observational studies. Human physiological studies and controlled balance studies show a clear but only a very small depressant effect of caffeine itself on intestinal calcium absorption, and no effect on total 24-h urinary calcium excretion. The epidemiologic studies showing a negative effect may be explained in part by an inverse relationship between consumption of milk and caffeine-containing beverages. Low calcium intake is clearly linked to skeletal fragility, and it is likely that a high caffeine intake is often a marker for a low calcium intake. The negative effect of caffeine on calcium absorption is small enough to be fully offset by as little as 1-2 tablespoons of milk. All of the observations implicating caffeine-containing beverages as a risk factor for osteoporosis have been made in populations consuming substantially less than optimal calcium intakes. There is no evidence that caffeine has any harmful effect on bone status or on the calcium economy in individuals who ingest the currently recommended daily allowances of calcium.

Fatores de risco da osteoporose: prevenção e detecção através do monitoramento clínico e genético

A osteoporose é uma doença sistêmica caracterizada pela baixa massa óssea e deterioração da micro arquitetura do tecido ósseo. Consequentemente existe um aumento na fragilidade do osso e suscetibilidade à fratura, que é considerada o efeito clínico mais importante deste processo. Muitos estudos que se utilizam de modelos em gêmeos ou pais e seus descendentes têm confirmado o papel da herança genética no pico de massa óssea, na verdade o maior fator de risco da fratura. Neste artigo de revisão, são enfocados os prováveis genes envolvidos no processo de osteoporose, ressaltando a importância das interações entre gene- gene e gene-ambiente. Concernente à influência isolada do ambiente, são abordados os hábitos relacionados ao estilo de vida, à nutrição e ao tabagismo envolvidos no aparecimento dessa doença. Durante os próximos anos, o conhecimento baseado na genética molecular elucidará o processo osteoporótico. Do mesmo modo, os estudos clínicos se expandirão, visando contribuir para a detecção precoce da doença, permitindo assim a aplicação de medidas preventivas e terapêuticas adequadas.

Effects of caffeine, vitamin D, and other nutrients on quantitative phalangeal bone ultrasound in postmenopausal women

OBJECTIVE

We investigated the controversial effects of coffee and other nutrients on bone mass.

METHODS

In a study of 93 healthy postmenopausal women (mean +/- standard deviation: 57.3 +/- 7.1 y old and 8.9 +/- 7.5 y since menopause) selected on the basis of not having changed their eating habits since premenopause, not smoking, not exercising, not receiving hormone-replacement therapy, and having a weight in the range of 70% to 130% of their ideal weights, amplitude-dependent speed of sound (Ad-SOS) was determined by quantitative bone ultrasound, and a prospective 7-d diet survey evaluated the intake of caffeine and nutrients involved in calcium metabolism. Women were stratified according to their caffeine, calcium, and vitamin D intakes and ratios of calcium to phosphorus and to protein. Ad-SOS differed only with vitamin D intake and was greater in the group taking at leasst 400 IU/d (P < 0.0001).

RESULTS

In simple and multiple regression analyses, the only significant variable that affected Ad-SOS and nutrient intake was vitamin D (P < 0.0001). Phalangeal bone Ad-SOS was influenced only by the intake of vitamin D, not of caffeine or other nutrients.

CONCLUSIONS

This lack of effect of caffeine and protein may be related to good nutritional intake or the low levels of caffeine consumed.

Focus on Communications: Communicating the Message: Clarifying the Controversies About Caffeine

Today's "coffee culture" and the widespread availability of caffeine-containing foods and beverages fuel the ongoing study of caffeine and its subsequent coverage by the media. Although the media has become influential in communicating health and nutrition information to the public, coverage of emerging science, such as the study of caffeine, does not necessarily bring clarity or improved understanding for consumers. This article highlights the current knowledge of caffeine's effects on health, with emphasis on the most common areas of interest and confusion. To address persistent misperceptions about caffeine, this article also accentuates the need for nutrition professionals to help put the findings of caffeine research into perspective and suggests practical ways to do this.

Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes

BACKGROUND

The role of caffeine as a risk factor for bone loss is controversial.

OBJECTIVE

Our goals were 1) to compare in both a cross-sectional study and a 3-y longitudinal study the bone mineral density (BMD) of postmenopausal women consuming high or low amounts of caffeine and 2) to study the interaction between caffeine intake, vitamin D receptor (VDR) polymorphism, and BMD in the longitudinal study.

DESIGN

The results are derived from cross-sectional measurements of BMD in 489 elderly women (aged 65-77 y) and from longitudinal measurements made in 96 of these women who were treated with a placebo for 3 y. Changes in BMD were adjusted for confounding factors and were compared between groups with either low (< or =300 mg/d) or high (>300 mg/d) caffeine intakes and between the VDR genotype subgroups of the low- and high-caffeine groups.

RESULTS

Women with high caffeine intakes had significantly higher rates of bone loss at the spine than did those with low intakes (-1.90 +/- 0.97% compared with 1.19 +/- 1.08%; P = 0.038). When the data were analyzed according to VDR genotype and caffeine intake, women with the tt genotype had significantly (P = 0.054) higher rates of bone loss at the spine (-8.14 +/- 2.62%) than did women with the TT genotype (-0.34 +/- 1.42%) when their caffeine intake was >300 mg/d.

CONCLUSIONS

Intakes of caffeine in amounts >300 mg/d ( approximately 514 g, or 18 oz, brewed coffee) accelerate bone loss at the spine in elderly postmenopausal women. Furthermore, women with the tt genetic variant of VDR appear to be at a greater risk for this deleterious effect of caffeine on bone.

Effect of coffee consumption on bone metabolism

The effects of coffee on bone metabolism are still controversial, although several studies have suggested that caffeine and/or heavy coffee consumption is associated with a significant increase in risk of fracture, osteoporosis, and periodontal disease. Therefore, we sought to clarify the relationship between coffee consumption and bone metabolism using male Wistar rats. Forty-eight male Wistar rats were assigned to three treatment groups including a control-diet group (control, n = 16, coffee-free diet), a 0.62% coffee-diet group (low caffeine, n = 16, diet supplemented with 6.2 g/kg of the control diet), and a 1.36% coffee-diet group (high caffeine, n = 16, diet supplemented with 13.6 g/kg of the control diet), and animals were maintained on an experimental diet for 140 days. Although caffeine in serum was not detected in rats fed the control diet, low-intake coffee for 140 days led to an increase in caffeine concentration to 0.53 +/- 0.11 microg/mL and high-intake coffee led to an increase of 1.77 +/- 0.22 microg/mL. No significant differences in body weight change, serum and urinary biochemical markers of bone metabolism, and bone histomorphometry were found between the coffee-diet groups and the control-diet group, except that urinary phosphorus excretion after 140 days of both coffee diets was significantly increased compared with controls (p < 0.05). In addition, the coffee diets were not associated with differences in tumor necrosis factor-alpha and interleukin-6, which have been implicated in the pathogenesis of bone loss together with interleukin-1beta. In conclusion, the present study strongly indicates that coffee does not stimulate bone loss in rats.

Is caffeine associated with bone mineral density in young adult women?

BACKGROUND

By increasing the urinary excretion of calcium, caffeine consumption may reduce bone mineral density (BMD) and subsequently increase the risk for osteoporotic fracture. Although negative associations between caffeine consumption and BMD have been reported for postmenopausal women, in particular for those who consume low amounts of dietary calcium, the relation between caffeine and BMD in younger women is unclear. Therefore, we evaluated the association between caffeine consumption and BMD in a cross-sectional study of 177 healthy white women, age 19-26 years, who attended a Midwestern university.

METHODS

Average caffeine intake (milligrams per day) was calculated from self-reports of the consumption of coffee, decaffeinated coffee, tea, colas, chocolate products, and select medications during the previous 12 months (mean caffeine intake = 99. 9 mg/day). BMD (grams per square centimeter) at the femoral neck and the lumbar spine was measured by dual-energy X-ray absorptiometry.

RESULTS

After adjusting in linear regression models for potential confounders, including height, body mass index, age at menarche, calcium intake, protein consumption, alcohol consumption, and tobacco use, caffeine consumption was not a significant predictor of BMD. For every 100 mg of caffeine consumed, femoral neck BMD decreased 0.0069 g/cm(2) (95% confidence in terval [CI] = -0.0215, 0. 0076) and lumbar spine BMD decreased 0.0119 g/cm(2) (95% CI = -0. 0271, 0.0033). No single source of caffeine was significantly associated with a decrease in BMD. Furthermore, the association between caffeine consumption and BMD at either site did not differ significantly between those who consumed low levels of calcium (< or =836 mg/day) and those who consumed high levels of calcium (>836 mg/day).

CONCLUSIONS

Caffeine intake in the range consumed by young adult women is not an important risk factor for low BMD.

Nutrition in bone health revisited: a story beyond calcium

Osteoporosis is a complex, multi-factorial condition characterized by reduced bone mass and impaired micro-architectural structure, leading to an increased susceptibility to fractures. Although most of the bone strength (including bone mass and quality) is genetically determined, many other factors (nutritional, environmental and life-style) also influence bone. Nutrition is important modifiable factor in the development and maintenance of bone mass and the prevention and treatment of osteoporosis. Approximately 80-90% of bone mineral content is comprised of calcium and phosphorus. Other dietary components, such as protein, magnesium, zinc, copper, iron, fluoride, vitamins D, A, C, and K are required for normal bone metabolism, while other ingested compounds not usually categorized as nutrients (e.g. caffeine, alcohol, phytoestrogens) may also impact bone health. Unraveling the interaction between different factors; nutritional, environmental, life style, and heredity help us to understand the complexity of the development of osteoporosis and subsequent fractures. This paper reviews the role of dietary components on bone health throughout different stages of life. Each nutrient is discussed separately, however the fact that many nutrients are co-dependent and simultaneously interact with genetic and environmental factors should not be neglected. The complexity of the interactions is probably the reason why there are controversial or inconsistent findings regarding the contribution of a single or a group of nutrients in bone health.

Association of fractures with caffeine and alcohol in postmenopausal women: the Iowa Women's Health Study

OBJECTIVE

To assess whether alcoholic and caffeinated beverages are associated with risk of fractures in women.

SETTING

Population-based sample surveyed by post.

SUBJECTS

A total of 34 703 postmenopausal Iowan women aged 55-69 years were surveyed.

DESIGN

A cohort of women reported alcoholic and caffeinated beverage intake and were followed for 6.5 years for fracture occurrence. Relative risks (RR) and 95% confidence intervals (CI) were computed using Cox proportional hazards regression. Covariates included age, tobacco use, physical activity, body mass index (BMI), waist to hip ratio (WHR), oestrogen use and calcium intake.

RESULTS

At least one fracture was reported by 4378 women (389 upper arm, 288 forearm, 1128 wrist, 275 hip, 416 vertebral and 2920 other fractures). The adjusted RR for highest versus lowest caffeine intake quintiles was 1.09 (95% CI 0.99-1.21) for combined fracture sites. Wrist fractures were associated positively (RR for extreme quintiles 1.37, 95% CI 1.11-1.69) and upper arm fractures were negatively associated (RR 0.67, 95% CI 0.48-0.94) with caffeine intake. The age-adjusted RR of total fractures for highest versus lowest frequency of beer usage was 1.55 (95% CI 1.25-1.92) and for liquor was 1.25 (95% CI 1.03-1.54). No other association was found between any specific fracture site and alcohol intake.

CONCLUSIONS

We found a modest increase in fracture risk associated with highest caffeine intake, varying by site. Alcohol intake was low, but it also showed a weak positive association with fracture risk.

Osteoporosis and low bone mass in premenopausal and perimenopausal women

OBJECTIVE

To characterize the historical, clinical, and biochemical features of 111 young women (age, <55 years) referred for evaluation of osteoporosis or low bone mass.

METHODS

Women with a bone mineral density T score < or = -2.0 (N = 111) at one or more anatomic sites (by dual-energy x-ray absorptiometry) were assessed relative to anthropomorphic and biochemical characteristics and risk factors for osteoporosis.

RESULTS

Of 111 women with low bone mass or osteoporosis, 73 (66%) had identifiable causes of bone loss, of which estrogen deficiency (menopause, premenopausal estrogen deficiency) and conditions associated with estrogen deficiency (anorexia nervosa, cancer chemotherapy) were the most common. Prolonged use of glucocorticoids was the most common secondary cause of osteoporosis. Of 38 women with no identifiable cause of bone loss, 21 were premenopausal (mean age, 38 +/- 10 years [standard deviation]) and 17 were perimenopausal (mean age, 50 +/- 3 years). The mean lumbar spine T score was -2.18 +/- 1.0 in the premenopausal and -2.51 +/- 0.6 in the perimenopausal women. Nontraumatic fractures were reported by 42% of the premenopausal women and 18% of the perimenopausal women. A family history of osteoporosis was reported by 71% of the premenopausal and 47% of the perimenopausal women.

CONCLUSION

Most young women with osteoporosis or low bone mass had estrogen deficiency or another secondary cause of premature bone loss (or both). A subset of premenopausal and perimenopausal women, however, had no identifiable cause of bone loss. The strong family history of osteoporosis, especially in the premenopausal women, provides further support for current theories of a genetic predisposition to osteoporosis.

Bone status among postmenopausal women with different habitual caffeine intakes: a longitudinal investigation

OBJECTIVE

Caffeine consumption has been proposed as a risk factor for bone loss in postmenopausal women. Past epidemiologic studies on caffeine and bone have been confounded by covariates including cigarette and alcohol use, differing levels of physical activity and hormone replacement therapy. The purpose of the study was to use a longitudinal design to determine the relationship between habitual dietary caffeine intake and postmenopausal bone status.

METHODS

Data were collected at two time points separated by two years; 138 women with little or no exposure to tobacco or to drugs known to affect bone status were seen at Visit 1, and 112 returned for Visit 2. Ninety-two of these subjects had received no drugs known to affect bone status over the two-year interval and were kept in the sample. Nutrient and caffeine intake were assessed from three-day diet records. Bone measurements were made by dual energy x-ray absorptiometry (DXA).

RESULTS

Correlation analyses indicated no association between dietary caffeine intake and total body or femoral neck bone density or bone mass. Similarly, no associations were found between caffeine consumption and longitudinal changes in total body or femoral neck bone measurements. These results held true both with and without statistical adjustment for calcium intake.

CONCLUSIONS

This study does not support the idea that caffeine is a risk factor for bone loss in healthy postmenopausal women.

Tea and health

Tea is a pleasant, popular, socially accepted, economical, and safe drink that is enjoyed every day by hundreds of millions of people across all continents. Tea also provides a dietary source of biologically active compounds that help prevent a wide variety of diseases. It is the richest source of a class of antioxidants called flavonoids and contains many other beneficial compounds such as vitamins and fluoride. A growing body of evidence suggests that moderate consumption of tea may protect against several forms of cancer, cardiovascular diseases, the formation of kidney stones, bacterial infections, and dental cavities. Future research needs to define the actual magnitude of health benefits, establish the safe range of tea consumption associated with these benefits, and elucidate potential mechanisms of action.

Supplemental and complementary alternatives to hormone replacement therapy

Tables 1 and 2 offer a summary of information currently available on the sources, dosages, and proposed health benefits of the supplemental and complementary nutritional therapies that can be suggested as alternatives to hormone replacement therapy. These therapies have the additional benefit of being broadly available to women of all socioeconomic strata, and should be acceptable to women of various ethnicities and cultures. Adequate intakes (AI) of vitamins are recommended based on observational or experimentally determined approximations of the average nutrient intake, by a defined population or group, that appears to sustain a defined nutritional state (Food and Nutrition Boar, Institute of Medicine, 1997). Reviewing the empirical evidence concerning the use of vitamin supplements leads to the conclusion that doses higher than AI or recommended daily requirements is not warranted. For those individuals who choose to supplement, counseling should be provided to caution about tolerable upper limits, those maximum levels of nutrient intake judged unlikely to pose a risk for adverse health effects (Food and Nutrition Boar, Institute of Medicine). Supplemental and complementary therapy directed at ameliorating symptoms or reducing the risk of menopause related illness (osteoporosis and CHD) becomes a decision balance of the woman's preferences, risk and health history, and personal and financial resources. There appears to be some protection of morbidity and mortality from CHD with antioxidant dietary intake. Osteoporosis appears to be delayed with calcium supplementation. Menopausal symptoms, CHD risk, and osteoporosis risk appears to be reduced with phytoestrogen supplementation, although doses have not been established. Research concerning the safety and efficacy of these therapies continues. Findings from current clinical trials, such as the Women's Health Initiative may render these and additional alternative therapies to HRT more precise in the near future.

Combined effects of caffeine and prostaglandin E2 on the proliferation of osteoblast-like cells (UMR106-01)

BACKGROUND

The general public widely consumes caffeine (1,3,7-trimethylxanthine), which is contained in various foods, beverages and over-the-counter medications. We have shown previously that caffeine intake could affect bone metabolism in vivo.

METHODS

Because prostaglandin E2 (PGE2) is shown to be elevated in the periodontally diseased site, the possible interaction between caffeine and PGE2 was investigated in the present study using UMR106-01 rat osteoblast-like cells in vitro.

RESULTS

Although neither 0.1 mM caffeine nor 0.1 microg/ml of PGE2 alone showed any inhibitory effects on cell proliferation, the combination of caffeine and PGE2 showed significant inhibition. However, in order to have inhibitory effects, both caffeine and PGE2 had to be present at least 72 or 96 hours in the medium. Addition of the endogenous PGE2 synthesis inhibitor, indomethacin, showed no effects on cell proliferation. Neither cAMP-inducing agent IBMX (0.01 mM and 0.1 mM) nor forskolin (0.001 mM) inhibited cell proliferation, but combined with PGE2 these agents strongly inhibited proliferation as was observed with the combination of caffeine and PGE2, suggesting possibly that the increase of intracellular cAMP concentration plays an important role in the inhibitory effects of cell proliferation.

CONCLUSIONS

The present data for the first time demonstrate the possible implication of routine caffeine intake in the acceleration of pathological conditions of periodontitis. Thus, we propose that chronic caffeine intake is one of the possible risk factors in the advancement of pathology in the periodontitis patient. Further research in this area is warranted.

Dietary caffeine intake is not correlated with adolescent bone gain

OBJECTIVE

This study was conducted to determine whether dietary caffeine consumed by American white females between ages 12 to 18 affects total body bone mineral gain during ages 12 to 18 or affects hip bone density measured at age 18.

METHODS

The Penn State Young Women's Health Study is a longitudinal investigation of bone, endocrine and cardiovascular health in non-Hispanic, white, teenage women. Nutrient and food group intakes were obtained by averaging over 6 years of prospective diet records. The cohort, as of age 18, (n = 81) was separated into three subgroups according to mean daily caffeine intake averaged across ages 12 to 18. Group I (n = 37) consumed less than 25 mg caffeine per day; Group II (n = 33) consumed 25 to 50 mg caffeine per day; and Group III (n = 11) consumed greater than 50 mg caffeine per day. The group mean daily caffeine intakes (SD) were Group I = 14 (6) mg/day; Group II = 35 (7) mg/day; Group III = 77 (27) mg/day. Total body bone gain and hip bone density were determined by dual energy x-ray absorptiometry (DXA).

RESULTS

There were no significant differences among the three caffeine intake groups for total body bone mineral gain during the ages 12 to 18 or of hip bone density at age 18. The low caffeine intake group consumed more milk (and therefore more calcium) and more fruit per day than did the other two groups. Group III, the highest caffeine intake group, consumed more sugar per day than did the other two groups. The observed differences in nutrient and food intakes among the three groups were not associated with any differences in anthropometric measurements or bone gain among the three groups.

CONCLUSION

These findings indicate that dietary caffeine intake at levels presently consumed by American white, teenage women is not correlated with adolescent total bone mineral gain or hip bone density at age 18.

Women's knowledge of osteoporosis

Osteoporosis affects one in four women over the age of 65 and is a major cause of hip fractures that place women in nursing homes. In this study of 247 women, their knowledge of osteoporosis was assessed with the Facts on Osteoporosis Quiz. The instrument measured their responses to questions about self-care practices related to risk factors and preventive behavior associated with osteoporosis. Respondents came from occupational and primary health care settings and a health fair. The women ranged in age from 22 to 84 years. Findings indicated that the majority of women had inadequate knowledge of osteoporosis risk factors and preventive behavior.

Caffeine and the elderly

The most common source of dietary caffeine among the elderly is coffee, with consumption averaging about 200 mg/day. Because of the greater proportion of adipose tissue to lean body mass in older humans, and because caffeine is distributed essentially only through lean body mass, a dose of caffeine expressed as mg/kg total bodyweight may result in a higher plasma and tissue concentration in elderly compared with younger individuals. The metabolism of, and physiological responses to, caffeine is similar in elderly and younger individuals. However, there is a limited amount of evidence that responses to caffeine in some physiological systems may be greater in the elderly at doses in the 200 to 300 mg range. Although caffeine consumption increases urinary calcium levels similarly in both younger and older individuals, the preponderance of data suggest that caffeine has a greater impact on calcium metabolism and bone in older people. Evidence also suggests that increasing age is associated with increasing sensitivity to the pressor effects of caffeine. Caffeine appears to affect metabolic and neurological responses similarly in both young and elderly individuals, when differences in baseline performance are taken into account.