Vitamin D receptor gene polymorphisms and bone mass indices in post-menarchal Indian adolescent girls

High burden of hypovitaminosis D among the children and adolescents in South Asia: a systematic review and meta-analysis

BACKGROUND

Vitamin D is vital for the growth and development of children. While deficiency and/or insufficiency of vitamin D among South Asian children are frequently reported in the literature, the lack of a meta-analysis has left its true extent poorly characterized. In this study, we aimed to conduct a systematic review and perform meta-analyses of the prevalence of hypovitaminosis D among the children of the South Asian countries.

METHODS

Two major electronic search engines (PubMed and Scopus) and one database (Google scholar) were used; original studies, conducted among South Asian children and adolescents and published between 1 January 2001 and 31 December 2019. A random-effect meta-analysis was also performed to calculate the pooled prevalence of hypovitaminosis D followed by subgroup analyses for countries and age groups.

RESULTS

After applying inclusion and exclusion criteria, a total of 41 studies with a total population size of 18,233 were finally selected. The overall prevalence of hypovitaminosis D was 61% [95% CI: 46% to 71%] with highly significant heterogeneity (I2 = 99.72%; p < 0.0001). The average level of serum vitamin D ranged from 5 ng/mL to 34 ng/mL, with a weighted mean of 19.15 ng/mL (weighted standard deviation 11.59 ng/mL). Country-wise analysis showed that hypovitaminosis D in Afghanistan was the highest [96.2%; 95% CI: 91% to 99%], followed by Pakistan [94%; 95% CI: 90% to 96%], India [64%; 95% CI: 46% to 79%], Bangladesh [35.48%; 95% CI: 32% to 39%], Nepal [35%; 95% CI: 1% to 83%], and Sri Lanka [25%; 95% CI: 16% to 36%]. Age group analyses revealed that hypovitaminosis D was most prevalent among neonates [85%; 95% CI: 76% to 91%], followed by school-going children [57%; 95% CI: 33% to 80%], and preschool children [55%; 95% CI: 35% to 75%].

CONCLUSION

This study generates quantitative evidence and specific extent of hypovitaminosis D in the South Asian countries as a public health concern. Being the first systematic review for this region, results from this study will create awareness and will facilitate adopting mitigation strategies by the policymakers and the governments to address this problem.

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.

A systematic review and meta-analysis of prevalence of vitamin D deficiency among adolescent girls in selected Indian states

BACKGROUND:

Vitamin D deficiency among adolescents is an emerging public health priority as adolescence marks a period of rapid growth and the onset of the reproductive phase. However, lack of national prevalence data and intervention strategies is of public health concern.

OBJECTIVE:

The objective of this study was to determine the pooled prevalence of vitamin D deficiency among adolescent girls in selected Indian states.

METHODS:

A systematic literature review was performed using three different search engines. The searches yielded nine eligible articles. Study quality was assessed for 10 different criteria. Meta-analysis was performed to estimate pooled prevalence of vitamin D deficiency among adolescent girls and to assess the heterogeneity among selected studies.

RESULTS:

A sample of n=1352 was used to study prevalence among adolescent girls. The random effects combined estimate for overall prevalence was 25.70% (95% CI 3.89-2137.9). High heterogeneity (tau²=1.71, I²=100%) was observed and seven out of nine studies showed low to moderate risk and two showed high risk of bias. The test for overall effect was observed to be Z=0.77 ( p=0.44).

CONCLUSIONS:

High prevalence of vitamin D deficiency among adolescent girls identifies the need to introduce screening of adolescents and introduce proven public-health interventions such as fortification of foods to address deficiency.

Calcium plus vitamin D supplementation during pregnancy interacts with polymorphisms in the promoter region of the VDR gene to affect postpartum bone mass of Brazilian adolescent mothers: A randomized controlled trial

OBJECTIVE

We investigated whether calcium plus vitamin D supplementation interacts with polymorphisms in the VDR gene promoter region to affect changes on maternal bone mass from 5 to 20 wk postpartum in Brazilian adolescent mothers.

METHODS

Pregnant adolescents (14-19 y) randomly received calcium plus cholecalciferol (600 mg/d + 200 IU/d, n = 30) or placebo (n = 26) from 26 wk of pregnancy until parturition. Bone mineral content (BMC), bone area (BA), and bone mineral density (BMD) at total body, lumbar spine, total hip, and femoral neck were evaluated at 5 and 20 wk postpartum. Serum 25-hydroxyvitamin D (25[OH]D) and parathyroid hormone concentrations were measured. Real-time polymerase chain reaction was used for genotyping rs7139166 (1521 pb G > C) and rs4516035 (1012 pb A > G). Interactions between supplementation and polymorphisms were adjusted for significant covariates.

RESULTS

Changes in serum 25(OH)D from pregnancy to postpartum differed between supplemented and placebo groups for mothers carrying 1521 GG/1012 AA genotypes (P = 0.004). Only in the placebo group, mothers carrying 1521 GG/1012 AA had greater reduction in total BMD z score, femoral neck BMC, and BMD from 5 to 20 wk postpartum compared with those with 1521 GC/1012 AG (P < 0.05). In the placebo group, total hip BA decreased from 5 to 20 wk postpartum in adolescents with 1521 GG/1012 AA, but increased in those with 1521 GC/1012 AG (P < 0.05), in contrast to the supplemented group.

CONCLUSION

Calcium plus vitamin D supplementation during pregnancy interacted with polymorphisms in the VDR gene promoter region affecting postpartum bone loss. The increased supply of calcium and vitamin D appeared to minimize postpartum bone loss particularly in adolescents with 1521 GG/1012 AA.

Influence of Vitamin D Receptor Gene Fok1 Polymorphism on Bone Mass Accrual Post Calcium and Vitamin D Supplementation

OBJECTIVE

To examine the association of vitamin D receptor (VDR) gene polymorphisms of the Fok1 locus on bone mass accrual in Indian girls used to a low calcium intake.

METHODS

An intervention trial was undertaken in 102 girls aged 8-16 y, attending a state run school in Pune city, India. All girls received 500 mg calcium daily and 30,000 IU of vitamin D3 quarterly for one year. Dietary calcium intake was evaluated. Bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) were measured at total body using Dual Energy X-ray Absorptiometry (Lunar DPX-PRO). Polymorphisms of the Fok1 locus of the vitamin D Receptor (VDR) gene were detected using SYBR Green quantitative polymerase chain reaction.

RESULTS

The prevalence of Fok1 polymorphism was 43.1% (Ff), 9.8% (ff) and 47.1% (FF). At baseline, FF genotype had significantly lower BMD as compared to ff and Ff genotype (p < 0.05). At baseline, majority of girls (82.4%) were hypocalcemic with low calcium intake. Post-supplementation, FF genotype had significantly lower bone mass as compared to ff and Ff genotype. Significant increase in BMC [Ff (17.9%); ff (18.1%); FF (17.4%)], and BMD [Ff (5.4 %); ff (6.3%); FF (4.8%)] was observed post supplementation (p value < 0.05), though percentage increase in BMC and BMD was similar for three Fok1 polymorphisms (p > 0.1).

CONCLUSIONS

VDR gene polymorphism, as defined by Fok1 genotype had no positive influence on bone mass accrual in response to calcium supplementation.

Association between vitamin D receptor gene polymorphisms (Fok1 and Bsm1) and osteoporosis: a systematic review

Osteoporosis is a health concern characterized by reduced bone mineral density (BMD) and increased risk of fragility fractures. Many studies have investigated the association between genetic variants and osteoporosis. Polymorphism and allelic variations in the vitamin D receptor gene (VDR) have been found to be associated with bone mineral density. However, many studies have not been able to find this association. Literature review was conducted in several databases, including MEDLINE/Pubmed, Scopus, EMBASE, Ebsco, Science Citation Index Expanded, Ovid, Google Scholar, Iran Medex, Magiran and Scientific Information Database (SID) for papers published between 2000 and 2013 describing the association between Fok1 and Bsm1 polymorphisms of the VDR gene and osteoporosis risk. The majority of the revealed papers were conducted on postmenopausal women. Also, more than 50% studies reported significant relation between Fok1, Bsm1 and osteoporosis. Larger and more rigorous analytical studies with consideration of gene-gene and gene-environment interactions are needed to further dissect the mechanisms by which VDR polymorphisms influence osteoporosis.