Long-Term Effect of Randomization to Calcium and Vitamin D Supplementation on Health in Older Women : Postintervention Follow-up of a Randomized Clinical Trial.

BACKGROUND: Although calcium and vitamin D (CaD) supplementation may affect chronic disease in older women, evidence of long-term effects on health outcomes is limited. OBJECTIVE: To evaluate long-term health outcomes among postmenopausal women in the Women's Health Initiative CaD trial. DESIGN: Post hoc analysis of long-term postintervention follow-up of the 7-year randomized intervention trial of CaD. (ClinicalTrials.gov: NCT00000611). SETTING: A multicenter (n = 40) trial across the United States. PARTICIPANTS: 36 282 postmenopausal women with no history of breast or colorectal cancer. INTERVENTION: Random 1:1 assignment to 1000 mg of calcium carbonate (400 mg of elemental calcium) with 400 IU of vitamin D3 daily or placebo. MEASUREMENTS: Incidence of colorectal, invasive breast, and total cancer; disease-specific and all-cause mortality; total cardiovascular disease (CVD); and hip fracture by randomization assignment (through December 2020). Analyses were stratified on personal supplement use. RESULTS: For women randomly assigned to CaD versus placebo, a 7% reduction in cancer mortality was observed after a median cumulative follow-up of 22.3 years (1817 vs. 1943 deaths; hazard ratio [HR], 0.93 [95% CI, 0.87 to 0.99]), along with a 6% increase in CVD mortality (2621 vs. 2420 deaths; HR, 1.06 [CI, 1.01 to 1.12]). There was no overall effect on other measures, including all-cause mortality (7834 vs. 7748 deaths; HR, 1.00 [CI, 0.97 to 1.03]). Estimates for cancer incidence varied widely when stratified by whether participants reported supplement use before randomization, whereas estimates on mortality did not vary, except for CVD mortality. LIMITATION: Hip fracture and CVD outcomes were available on only a subset of participants, and effects of calcium versus vitamin D versus joint supplementation could not be disentangled. CONCLUSION: Calcium and vitamin D supplements seemed to reduce cancer mortality and increase CVD mortality after more than 20 years of follow-up among postmenopausal women, with no effect on all-cause mortality. PRIMARY FUNDING SOURCE: National Heart, Lung, and Blood Institute of the National Institutes of Health.

Calcium and vitamin D supplementation and cognitive impairment in the women's health initiative.

OBJECTIVES: To examine the effects of vitamin D and calcium on cognitive outcomes in elderly women. DESIGN: Post hoc analysis of a randomized double-blind placebo-controlled trial. SETTING: Forty Women's Health Initiative (WHI) clinical centers across the United States. PARTICIPANTS: Four thousand one hundred forty-three women aged 65 and older without probable dementia at baseline who participated in the WHI Calcium and Vitamin D Trial and the WHI Memory Study. INTERVENTION: Two thousand thirty-four women were randomized to receive 1,000 mg of calcium carbonate combined with 400 IU of vitamin D(3) (treatment) and 2,109 to placebo. MEASUREMENTS: Primary: classifications of probable dementia or mild cognitive impairment (MCI) based on a four-phase protocol that included central adjudication. Secondary: global cognitive function and individual cognitive subtests. RESULTS: Mean age of participants was 71. During a mean follow-up of 7.8 years, 39 participants in the treatment group and 37 in the placebo group developed incident dementia (hazard ratio (HR) = 1.11, 95% confidence interval (CI) = 0.71-1.74, P = .64). Likewise, 98 treatment participants and 108 placebo participants developed incident MCI (HR = 0.95, 95% CI = 0.72-1.25, P = .72). There were no significant differences in incident dementia or MCI or in global or domain-specific cognitive function between groups. CONCLUSION: There was no association between treatment assignment and incident cognitive impairment. Further studies are needed to investigate the effects of vitamin D and calcium separately, on men, in other age and ethnic groups, and with other doses.

A randomized controlled trial of calcium plus vitamin D supplementation and risk of benign proliferative breast disease.

Experimental evidence provides strong support for anti-carcinogenic effects of calcium and vitamin D with respect to breast cancer. Observational epidemiologic data also provide some support for inverse associations with risk. We tested the effect of calcium plus vitamin D supplementation on risk of benign proliferative breast disease, a condition which is associated with increased risk of breast cancer. We used the Women's Health Initiative randomized controlled trial. The 36,282 participants were randomized either to 500 mg of elemental calcium as calcium carbonate plus 200 IU of vitamin D(3) (GlaxoSmithKline) twice daily (n = 18,176) or to placebo (n = 18,106). Regular mammograms and clinical breast exams were performed. We identified women who had had a biopsy for benign breast disease and subjected histologic sections from the biopsies to standardized review. After an average follow-up period of 6.8 years, 915 incident cases of benign proliferative breast disease had been ascertained, with 450 in the intervention group and 465 in the placebo group. Calcium plus vitamin D supplementation was not associated with altered risk of benign proliferative breast disease overall (hazard ratio = 0.99, 95% confidence interval = 0.86-1.13), or by histologic subtype. Risk varied significantly by levels of age at baseline, but not by levels of other variables. Daily use of 1,000 mg of elemental calcium as calcium carbonate plus 400 IU of vitamin D(3) for almost 7 years by postmenopausal women did not alter the overall risk of benign proliferative breast disease.

Alcohol and folate consumption and risk of benign proliferative epithelial disorders of the breast.

Alcohol consumption has been associated with increased breast cancer risk and the increase in risk may be attenuated by adequate folate intake. However, their associations with the risk of benign proliferative epithelial disorders (BPEDs) of the breast, possible precursors of breast cancer, are not well understood. To investigate these associations, we conducted a cohort study among 68,132 postmenopausal women participating in the Women's Health Initiative randomized clinical trials. Women were prospectively followed and those reporting a breast procedure (open surgical biopsy or core needle biopsy) had histological sections obtained for central pathology review. A total of 1,792 women with BPED of the breast were identified over an average of 7.8 years of follow-up. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence limits (CLs) for the associations of interest. Compared to nondrinkers, total current alcohol intake of 30 g/day or more was not associated with BPED risk (HR = 0.98, 95% CL = 0.70, 1.38). The risk of BPED was not associated with folate intake from diet (highest vs. lowest quartile: HR = 1.10, 95% CL = 0.96, 1.26), from supplements (yes vs. no: HR = 1.05, 95% CL = 0.96, 1.16) or from all sources combined (highest vs. lowest quartile: HR = 1.11, 95% CL = 0.96, 1.27). Furthermore, there was no effect modification between alcohol and folate in relation to the risk of BPED. In conclusion, we observed that alcohol consumption and folate intake were not associated with altered risk of BPED, and that there was no effect modification between them in relation to the risk of BPED.

Calcium plus vitamin D supplementation and the risk of colorectal cancer.

BACKGROUND: Higher intake of calcium and vitamin D has been associated with a reduced risk of colorectal cancer in epidemiologic studies and polyp recurrence in polyp-prevention trials. However, randomized-trial evidence that calcium with vitamin D supplementation is beneficial in the primary prevention of colorectal cancer is lacking. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 36,282 postmenopausal women from 40 Women's Health Initiative centers: 18,176 women received 500 mg of elemental calcium as calcium carbonate with 200 IU of vitamin D3 [corrected] twice daily (1000 mg of elemental calcium and 400 IU of vitamin D3) and 18,106 received a matching placebo for an average of 7.0 years. The incidence of pathologically confirmed colorectal cancer was the designated secondary outcome. Baseline levels of serum 25-hydroxyvitamin D were assessed in a nested case-control study. RESULTS: The incidence of invasive colorectal cancer did not differ significantly between women assigned to calcium plus vitamin D supplementation and those assigned to placebo (168 and 154 cases; hazard ratio, 1.08; 95 percent confidence interval, 0.86 to 1.34; P=0.51), and the tumor characteristics were similar in the two groups. The frequency of colorectal-cancer screening and abdominal symptoms was similar in the two groups. There were no significant treatment interactions with baseline characteristics. CONCLUSIONS: Daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal women. The long latency associated with the development of colorectal cancer, along with the seven-year duration of the trial, may have contributed to this null finding. Ongoing follow-up will assess the longer-term effect of this intervention. (ClinicalTrials.gov number, NCT00000611.).