Biomedical subjects

Iris Granek

Publications and source records attributed to Iris Granek.

5 recordsLinked to original sources

PubMed2006

Calcium plus vitamin D supplementation and the risk of fractures.

BACKGROUND: The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal. METHODS: We recruited 36,282 postmenopausal women, 50 to 79 years of age, who were already enrolled in a Women's Health Initiative (WHI) clinical trial. We randomly assigned participants to receive 1000 mg of elemental [corrected] calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo. Fractures were ascertained for an average follow-up period of 7.0 years. Bone density was measured at three WHI centers. RESULTS: Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01). Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture (95 percent confidence interval, 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10), and 0.96 for total fractures (0.91 to 1.02). The risk of renal calculi increased with calcium plus vitamin D (hazard ratio, 1.17; 95 percent confidence interval, 1.02 to 1.34). Censoring data from women when they ceased to adhere to the study medication reduced the hazard ratio for hip fracture to 0.71 (95 percent confidence interval, 0.52 to 0.97). Effects did not vary significantly according to prerandomization serum vitamin D levels. CONCLUSIONS: Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density, did not significantly reduce hip fracture, and increased the risk of kidney stones. (ClinicalTrials.gov number, NCT00000611.).

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PubMed2006

Low-fat dietary pattern and risk of cardiovascular disease: the Women's Health Initiative Randomized Controlled Dietary Modification Trial.

CONTEXT: Multiple epidemiologic studies and some trials have linked diet with cardiovascular disease (CVD) prevention, but long-term intervention data are needed. OBJECTIVE: To test the hypothesis that a dietary intervention, intended to be low in fat and high in vegetables, fruits, and grains to reduce cancer, would reduce CVD risk. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial of 48,835 postmenopausal women aged 50 to 79 years, of diverse backgrounds and ethnicities, who participated in the Women's Health Initiative Dietary Modification Trial. Women were randomly assigned to an intervention (19,541 [40%]) or comparison group (29,294 [60%]) in a free-living setting. Study enrollment occurred between 1993 and 1998 in 40 US clinical centers; mean follow-up in this analysis was 8.1 years. INTERVENTION: Intensive behavior modification in group and individual sessions designed to reduce total fat intake to 20% of calories and increase intakes of vegetables/fruits to 5 servings/d and grains to at least 6 servings/d. The comparison group received diet-related education materials. MAIN OUTCOME MEASURES: Fatal and nonfatal coronary heart disease (CHD), fatal and nonfatal stroke, and CVD (composite of CHD and stroke). RESULTS: By year 6, mean fat intake decreased by 8.2% of energy intake in the intervention vs the comparison group, with small decreases in saturated (2.9%), monounsaturated (3.3%), and polyunsaturated (1.5%) fat; increases occurred in intakes of vegetables/fruits (1.1 servings/d) and grains (0.5 serving/d). Low-density lipoprotein cholesterol levels, diastolic blood pressure, and factor VIIc levels were significantly reduced by 3.55 mg/dL, 0.31 mm Hg, and 4.29%, respectively; levels of high-density lipoprotein cholesterol, triglycerides, glucose, and insulin did not significantly differ in the intervention vs comparison groups. The numbers who developed CHD, stroke, and CVD (annualized incidence rates) were 1000 (0.63%), 434 (0.28%), and 1357 (0.86%) in the intervention and 1549 (0.65%), 642 (0.27%), and 2088 (0.88%) in the comparison group. The diet had no significant effects on incidence of CHD (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.90-1.06), stroke (HR, 1.02; 95% CI, 0.90-1.15), or CVD (HR, 0.98; 95% CI, 0.92-1.05). Excluding participants with baseline CVD (3.4%), the HRs (95% CIs) for CHD and stroke were 0.94 (0.86-1.02) and 1.02 (0.90-1.17), respectively. Trends toward greater reductions in CHD risk were observed in those with lower intakes of saturated fat or trans fat or higher intakes of vegetables/fruits. CONCLUSIONS: Over a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVD risk. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov Identifier: NCT00000611.

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PubMed2006

Benchmarks for designing two-stage studies using modified mini-mental state examinations: experience from the Women's Health Initiative Memory Study.

BACKGROUND: The most efficient approach for studies examining the incidence of dementia involves a brief screening instrument to identify participants for more extensive testing to identify cognitive impairment. The modified mini-mental state examination (3MS) is commonly used as this initial screen in such two-stage designs, however its properties for this role require further study. PURPOSE: We use data from the Women's Health Initiative Memory Study to contrast design options in two-stage designs. METHODS: This trial enrolled 7251 participants with nine or more years of education who were aged 65-79 and followed an average of four to five years. Logistic regression was used to examine the case yields at varying two-stage 3MS cutpoints. The efficiency of using different examination schedules and restricting enrollment to higher risk women was examined. RESULTS: Probable dementia is associated with marked decline in 3MS scores. The percentages of women classified with probable dementia ranged from 7.95% (3MS 85-88) to 50.0% (3MS < 70). The numbers [95% confidence interval] of enrolled women necessary to detect one case of probable dementia (four-year follow-up) for baseline 3MS scores of 100, 95, 90 and 85 were estimated as 1477 [389, 5618], 253 [134, 481], 53 [34, 85], and 14 [9, 23], respectively. Compared to annual testing, administration every two years increased the number of required enrollees by 11%, but decreased the number of test administrations by 46%. LIMITATIONS: Our findings are influenced by the characteristics of our study group, its rates of retention, and the study protocol, and may not fully generalize to other settings. CONCLUSIONS: The 3MS can serve as an efficient basis for two-stage study designs and a cutpoint of < or = 88 is reasonable for populations with similar characteristics. Studies may improve efficiency by using the 3MS during screening to eliminate women with low risk for dementia and by conducting testing every two years.

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PubMed2005

Effects of conjugated equine estrogen on health-related quality of life in postmenopausal women with hysterectomy: results from the Women's Health Initiative Randomized Clinical Trial.

BACKGROUND: The Women's Health Initiative (WHI) clinical trial of conjugated equine estrogens (CEEs), involving 10,739 postmenopausal women with hysterectomy, aged 50 to 79 years, was stopped early owing to lack of overall health benefit and increased risk of stroke. Because CEE is still prescribed for treatment of menopausal symptoms and prevention of osteoporosis, it is important to understand the overall impact of this therapy on health-related quality of life (HRQOL). METHODS: All participants completed 6 specific measures of quality of life at baseline and 1 year, and a subsample (n = 1189) also completed the questions 3 years after randomization. Changes in scores were analyzed for treatment effect. RESULTS: Randomization to CEE was associated with a statistically significant but small reduction in sleep disturbance at year 1 compared with baseline (mean benefit, 0.4 points on a 20-point scale) and a statistically significant but small negative effect on social functioning (mean effect, -1.3 points on a 100-point scale). There were no significant improvements due to CEE in the areas of general health, physical functioning, pain, vitality, role functioning, mental health, depressive symptoms, cognitive function, or sexual satisfaction at year 1. A subgroup examined 3 years after baseline had no significant benefits for any HRQOL outcomes. Among women aged 50 to 54 years with moderate to severe vasomotor symptoms at baseline, CEE did not improve any of the HRQOL variables at year 1. CONCLUSION: In this trial of postmenopausal women with prior hysterectomy, oral CEE did not have a clinically meaningful effect on HRQOL.

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PubMed2003

Research staff turnover and participant adherence in the Women's Health Initiative.

Maintaining participant adherence is a prerequisite for successful completion of randomized controlled trials requiring long-term follow-up. While patient characteristics influencing adherence are well studied, the influence of contact with clinical staff on this process has received almost no attention. To address this issue the authors evaluated the association of turnover in key clinical research staff with measures of participant adherence to protocol requirements at 40 clinical centers participating in the Women's Health Initiative (WHI), a large multicenter study. Key staff turnover in positions with potential influence on maintaining participant adherence in the Dietary Modification Clinical Trial (DM-CT) and the two Menopausal Hormone Therapy Clinical Trials (HT-CT) of the WHI was determined at each clinical center. Three prospectively established measures of participant adherence for the DM-CT and HT-CT were related to key staff turnover at each clinical center by staff category. More frequent turnover of the clinic practitioner, clinic manager, and principal investigator positions was significantly (p<0.05) associated with lower participant adherence in the HT-CT but was not associated with DM-CT participant adherence. More frequent turnover of the lead nutritionist was not associated with HT-CT participant adherence but was significantly (p<0.05) associated with one measure of decreased DM-CT participant adherence, as would be expected since the lead nutritionist did not typically see the HT-CT participants. These significant and plausible associations suggest that providing consistent contact with key staff in randomized, controlled clinical trials may facilitate long-term participant adherence. Further prospective study exploring process evaluation of the provider side of controlled trial conduct is indicated.

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