Familiality and partitioning the variability of femoral bone mineral density in women of child-bearing age

The contributions of polygenic loci and environmental factors to femoral bone mineral density (BMD in g/cm 2 ) variability were estimated in modified family sets consisting of women of child-bearing age. Femoral BMDs were measured in 535 women who were members of 137 family sets consisting minimally of an index, her sister, and unrelated female control. The family set could also include multiple sisters and first cousins. Women included in these family sets were all between 20 and 40 year of age to minimize the cohort effects of maturation and menopause on measures of BMD. BMDs were measured at three femoral sites using dual photon densitometry. Values were regressed on age and Quetelet Index which explained 13–15% of the variability in BMD (dependent on site). Subsequent variance components analysis on the residuals indicated that unmeasured polygenic loci accounted for substantial additional variability: 67% for femoral neck, 58% for Wards triangle, and 45% for trochanter. These results suggest that polygenic loci account for approximately half of the variability in maxmal femoral BMD.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48002/1/223_2004_Article_BF00298785.pd

Does back pain predict subsequent fracture in postmenopausal women?

This longitudinal study was undertaken to determine if back pain of postmenopausal women can well predict fragility fracture during 7-year follow-up. In 1983–84, 434 Caucasian women aged 55-80 years were examined at baseline. The incidence of fractures that occurred in the following 7 years and changes of radial bone mineral density (BMD) over 5 years were obtained. There was no significant association between baseline back pain and 7-year fracture incidence after baseline assessment (OR=1.137, [95%CI 0.674, 1.916]). However, the odds ratio in the association between 7-year fracture incidence and a prior history of back pain was 1.686, [95%CI 0.925, 3.073]. This association was statistically significant (OR=2.126, [95%CI 1.409, 2.844]) when age, baseline BMD, constitution, physical activity levels, and baseline back pain were taken into account. Although pain is subject to information bias in its reporting, it is suggested that a history of previous back pain could be a good predictor for postmenopausal fracture

Sex steroid metabolism polymorphisms and mammographic density in pre- and early perimenopausal women

Introduction: We examined the association between mammographic density and single-nucleotide polymorphisms (SNPs) in genes encoding CYP1A1, CYP1B1, aromatase, 17β-HSD, ESR1, and ESR2 in pre- and early perimenopausal white, African-American, Chinese, and Japanese women.Methods: The Study of Women's Health Across the Nation is a longitudinal community-based cohort study. We analyzed data from 451 pre- and early perimenopausal participants of the ancillary SWAN Mammographic Density study for whom we had complete information regarding mammographic density, genotypes, and covariates. With multivariate linear regression, we examined the relation between percentage mammographic breast density (outcome) and each SNP (primary predictor), adjusting for age, race/ethnicity, parity, cigarette smoking, and body mass index (BMI).Results: After multivariate adjustment, the CYP1B1 rs162555 CC genotype was associated with a 9.4% higher mammographic density than the TC/TT genotype (P = 0.04). The CYP19A1 rs936306 TT genotype was associated with 6.2% lower mammographic density than the TC/CC genotype (P = 0.02). The positive association between CYP1A1 rs2606345 and mammographic density was significantly stronger among participants with BMI greater than 30 kg/m2than among those with BMI less than 25 kg/m2(Pinteraction= 0.05). Among white participants, the ESR1 rs2234693 CC genotype was associated with a 7.0% higher mammographic density than the CT/TT genotype (P = 0.01).Conclusions: SNPs in certain genes encoding sex steroid metabolism enzymes and ESRs were associated with mammographic density. Because the encoded enzymes and ESR1 are expressed in breast tissue, these SNPs may influence breast cancer risk by altering mammographic density. © 2009 Crandall; licensee BioMed Central Ltd

Body size, estrogen use and thiazide diuretic use affect 5-year radial bone loss in postmenopausal women

Understanding factors associated with more rapid bone mineral loss among aging women is important for establishing preventive strategies for intervention. This study reports factors associated with the 5-year change in radial bone mineral density (BMD) determined prospectively in 435 women aged 55–80 years at baseline. The baseline study included measurement of radial BMD (gm/cm 2 ) by single photon densitometry and personal interview. The baseline protocol was replicated 5 years later in a follow-up study. Women with a lower baseline weight or Quetelet index, smaller triceps skinfold and less arm muscle area had significantly greater 5-year bone loss ( p =0.001). Current users of estrogens had less radial bone loss (2.8% vs 7.3%, p =0.0005) than women not currently using estrogens. Current users of estrogen had significantly less 5-year loss if use had been for 5 years or longer (−1.0% vs −6.9%, p =0.05). Current users of the thiazide class of medications had less 5-year radial bone loss (5.0% vs 7.4%, p =0.0035) than women without current thiazide use. Baseline dietary calcium, alcohol consumption and smoking were not associated with BMD change. This suggests that greater body size, and current use of estrogens or thiazide antihypertensives are associated with less radial bone mass loss in a 5-year period among postmenopausal women.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45913/1/198_2005_Article_BF01637317.pd