Poor bone health in underprivileged Indian girls: an effect of low bone mass accrual during puberty

Impact of Adolescent Pregnancy on Bone Density in Underprivileged Pre-Menopausal Indian Women

High prevalence (31.5%) of adolescent pregnancies (AP) have been reported in India. Reports suggest that pregnancy during adolescence may have deleterious effects on peak bone mass. Very few studies have described the long-term effects of a history of AP on bone mass. The objective of this study was to compare bone mineral density (BMD) and bone geometry of premenopausal women with first childbirth during adolescence (i.e., before age of 19 years) or after 20 years. A cross-sectional study was conducted in 242 women (age 28.0-54.5 years) from Pune, India (November, 2015 to November, 2017). Women were divided into 2-groups: Group-1: women-who had 1st-pregnancy and childbirth before 19 years of age (AP n = 131) and Group-2: women-who had 1st pregnancy after 20 years of age (non-AP n = 111). Demographic data, anthropometric measurements, and biochemical tests were performed using standard protocols. Physical activity and nutrient intakes were recorded using validated questionnaires. Areal BMD and bone geometry were measured using Dual-Energy-Absorptiometry-DXA (Lunar-iDXA, GE Healthcare) and peripheral-quantitative-computed-tomography-pQCT (XCT2000, Stratec Inc.). Mean age of the study group was 37 ± 4.6 years; in women from group-1 mean age at first delivery was 16.9 ± 1.6 years as against 22.6 ± 3.1 years in group-2. Both groups were similar in body mass index and socioeconomic status. pQCT measured radial diaphyseal cortical thickness (1.97 ± 0.3 mm vs 1.88 ± 0.3 mm resp., p = 0.016, periosteal circumference (38.0 ± 3.6 mm vs 36.7 ± 2.5 mm, resp. p = 0.016), total bone area (114.3 ± 24.8 mm2 vs 108.7 ± 14.7 mm2 resp. p = 0.026) and stress-strain index (SSI = 217 ± 75 vs 201 ± 40 mm3 resp. p = 0.042) were significantly higher in group-1 than group-2. After adjusting for anthropometric and lifestyle parameters, pQCT measured cortical thickness (1.98 ± 0.03 mm in group-1, 1.87 ± 0.03 mm group-2, p = 0.01, mean ± SE) and iDXA derived aBMD at forearm were still significantly higher (0.599 ± 0.006 g/cm3 vs 0.580 ± 0.006 g/cm3, p = 0.023) in Group-1. Our data suggest that women with a history of adolescent pregnancy had better bone geometry and higher aBMD at radius in later years. We speculate that early exposure to pregnancy resulted in higher aBMD at the radius and induced changes at radial diaphysis with bones becoming thicker and wider among these women.

Socioeconomic position and body composition in childhood in high- and middle-income countries: a systematic review and narrative synthesis

BACKGROUND

The relation between socioeconomic position (SEP) and obesity measured by body mass index (BMI), a measure of weight for height, has been extensively reviewed in children, showing consistent associations between disadvantaged SEP and higher BMI in high-income countries (HICs) and lower BMI in middle-income countries (MICs). Fat mass (FM), a more accurate measure of adiposity, and fat-free mass (FFM) are not captured by BMI, but have been shown to track from childhood to adulthood, and be important for cardiovascular health and functional outcomes in later life. It is not clear whether body composition is associated with SEP. We systematically reviewed the association between SEP and body composition in childhood.

METHODS

A systematic review was carried out following PRISMA guidelines. The protocol was pre-registered with PROSPERO (CRD42019119937). Original studies in the English language, which examined the association between SEP and body composition in childhood, were included. An electronic search of three databases was conducted. Two independent reviewers carried out screening, data extraction and quality assessment. Due to heterogeneity in results, a narrative synthesis was conducted. Heterogeneity in findings according to SEP, sex, body composition measure and country income level was investigated.

RESULTS

50 papers were included, the majority from HICs. No papers were from low-income countries. Disadvantage in childhood was associated with greater FM and lower FFM in HICs, but with lower FM and lower FFM in MICs. When measures of FFM indexed to height were used there was no evidence of associations with SEP. In HICs, more studies reported associations between disadvantaged SEP and higher FM among girls comparative to boys.

CONCLUSIONS

Inequalities in FM are evident in HICs and, in the opposite direction, in MICs and follow similar trends to inequalities for BMI. Inequalities in height are likely important in understanding inequalities in FFM.

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.

School-based calcium-vitamin D with micronutrient supplementation enhances bone mass in underprivileged Indian premenarchal girls

Low adult bone mass is linked to osteoporosis and fractures and is dependent on the extent of childhood and adolescent bone mineralization. The aim of the study was to investigate the effect of 1-year supplementation of calcium, multivitamin with zinc along with vitamin-D on bone mass accrual of school-going premenarchal girls from low income groups in Pune, India. Double-blind, matched-pair, cluster, randomization study was carried out in 214 premenarchal girls (8-12 years) from 2 schools in Pune, India. The two schools together formed 3 classes with 3 clusters each of age-matched girls of which one cluster was allocated to either one of the intervention groups (Ca-group:500 mg/d calcium, Ca+MZ-group:500 mg/d calcium+multivitamin tablet containing 15 mg/d zinc) or control group (C-group: multivitamin tablet without any minerals); all subjects received vitamin-D supplementation. Anthropometry, biochemical parameters, total body bone mineral content (TBBMC) and bone mineral density (TBBMD) (Dual energy X-ray absorptiometry) were assessed at baseline and endline. Post supplementation, mean percent increase in TBBMC was significantly higher in Ca-group (22.3%) and Ca+MZ-group (20.8%) compared to C-group (17.6%) (p<0.05) with no significant differences observed between Ca+MZ and Ca groups (p>0.1). Improvement in TBBMC-for-age Z-scores was higher in the two calcium supplemented groups (13.6%-22%) compared to the C-group (no improvement). Calcium supplementation, with or without multivitamins and zinc, showed a promising improvement in bone health especially with regards to improvement in bone related Z-scores in our population of underprivileged premenarchal girls.