BACKGROUND: The relationship between serum 25-hydroxyvitamin D [25(OH) vitamin D] concentration and hip fractures is unclear. OBJECTIVE: To see whether low serum 25(OH) vitamin D concentrations are associated with hip fractures in community-dwelling women. DESIGN: Nested case-control study. SETTING: 40 clinical centers in the United States. PARTICIPANTS: 400 case-patients with incident hip fracture and 400 control participants matched on the basis of age, race or ethnicity, and date of blood draw. Both groups were selected from 39 795 postmenopausal women who were not using estrogens or other bone-active therapies and who had not had a previous hip fracture. MEASUREMENTS: Serum 25(OH) vitamin D was measured and patients were followed for a median of 7.1 years (range, 0.7 to 9.3 years) to assess fractures. RESULTS: Mean serum 25(OH) vitamin D concentrations were lower in case-patients than in control participants (55.95 nmol/L [SD, 20.28] vs. 59.60 nmol/L [SD, 18.05]; P = 0.007), and lower serum 25(OH) vitamin D concentrations increased hip fracture risk (adjusted odds ratio for each 25-nmol/L decrease, 1.33 [95% CI, 1.06 to 1.68]). Women with the lowest 25(OH) vitamin D concentrations (< or =47.5 nmol/L) had a higher fracture risk than did those with the highest concentrations (> or =70.7 nmol/L) (adjusted odds ratio, 1.71 [CI, 1.05 to 2.79]), and the risk increased statistically significantly across quartiles of serum 25(OH) vitamin D concentration (P for trend = 0.016). This association was independent of number of falls, physical function, frailty, renal function, and sex-steroid hormone levels and seemed to be partially mediated by bone resorption. LIMITATIONS: Few case-patients were nonwhite women. Bone mineral density and parathyroid hormone levels were not accounted for in the analysis. CONCLUSION: Low serum 25(OH) vitamin D concentrations are associated with a higher risk for hip fracture.

OBJECTIVE: To identify predictors of dietary change to and maintenance of a low-fat eating pattern (or = 5 servings fruits/vegetables daily, and > or = 6 servings grains daily) among a cohort of postmenopausal women. Candidate predictors included intrapersonal, interpersonal, intervention program characteristics, and clinical center. DESIGN: Longitudinal study within the Women's Health Initiative Dietary Modification Trial. Dietary change was evaluated after 1 year of participation in the Women's Health Initiative Dietary Modification Trial, and dietary maintenance after 3 years. SUBJECTS: Postmenopausal women aged 50 to 79 years at baseline who were randomized to the intervention arm of the Women's Health Initiative Dietary Modification Trial (n=19,541). STATISTICAL ANALYSIS: Univariate and multivariate linear regression analysis was performed and associations evaluated between candidate predictors and each of the three dietary goals: percent energy from fat, fruit/vegetable servings, and grain servings. RESULTS: Year 1 (change) predictors of percent energy from fat (PCONCLUSIONS: The strongest predictors of dietary change and maintenance were attending intervention sessions and self-monitoring dietary intake. Novel was the finding that optimism predicted dietary change.

OBJECTIVE: To determine the effect of hormone therapy on arthroplasty rates. METHODS: We examined data from the Women's Health Initiative placebo-controlled, double-blind, randomized trials. Community-dwelling women ages 50-79 years were enrolled at 40 US clinics. Women with prior arthroplasty were excluded, yielding a sample size of 26,321 subjects. Women who had had hysterectomies (n = 10,272) were randomly assigned to receive 0.625 mg/day conjugated equine estrogens (n = 5,076), or placebo (n = 5,196), with a mean followup of 7.1 years. Those who had not had hysterectomies (n = 16,049) were randomly assigned to receive estrogen plus progestin (n = 8,240), given as 0.625 mg/day conjugated equine estrogens plus 2.5 mg/day medroxyprogesterone acetate, or placebo (n = 7,809), with a mean followup of 5.6 years. Participants reported hospitalizations, and arthroplasties were identified by procedure codes. Arthroplasties due to hip fracture were censored. Cox proportional hazards regression was used to assess hazard ratios (HRs) and 95% confidence intervals (95% CIs) using intent-to-treat methods and outcome of time to first procedure. RESULTS: In the estrogen-alone trial, women receiving hormone therapy had significantly lower rates of any arthroplasty (HR 0.84 [95% CI 0.70-1.00], P = 0.05). However, this effect was borderline statistically significant for hip arthroplasty (HR 0.73 [95% CI 0.52-1.03], P = 0.07), and not significant for knee arthroplasty (HR 0.87 [95% CI 0.71-1.07], P = 0.19). In the estrogen-plus-progestin trial, there was no association for total arthroplasty (HR 0.99 [95% CI 0.82-1.20], P = 0.92) or for individual hip (HR 1.14 [95% CI 0.83-1.57], P = 0.41) or knee (HR 0.91 [95% CI 0.72-1.15], P = 0.41) arthroplasties. CONCLUSION: These data suggest that hormone therapy may influence joint health, but this observed decrease in risk may be limited to unopposed estrogen and may possibly be more important in hip than in knee osteoarthritis.