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Racial/Ethnic Differences in 25-Hydroxy Vitamin D and Parathyroid Hormone Levels and Cardiovascular Disease Risk Among Postmenopausal Women.
Zhang, X, Tu, W, Manson, JE, Tinker, L, Liu, S, Cauley, JA, Qi, L, Mouton, C, Martin, LW, Hou, L, et al
Journal of the American Heart Association. 2019;(4):e011021
Abstract
Background Recent evidence suggests that racial/ethnic differences in circulating levels of free or bioavailable 25-hydroxy vitamin D (25[ OH ]D) rather than total 25( OH )D may explain apparent racial disparities in cardiovascular disease ( CVD ). We prospectively examined black-white differences in the associations of total, free, and bioavailable 25( OH )D, vitamin D-binding protein, and parathyroid hormone levels at baseline with incident CVD (including nonfatal myocardial infarction, nonfatal stroke, and CVD death) in postmenopausal women. Methods and Results We conducted a case-cohort study among 79 705 postmenopausal women, aged 50 to 79 years, who were free of CVD at baseline in the WHI-OS (Women's Health Initiative Observational Study). A subcohort of 1300 black and 1500 white participants were randomly chosen as controls; a total of 550 black and 1500 white women who developed incident CVD during a mean follow-up of 11 years were chosen as cases. We directly measured total 25( OH )D, vitamin D-binding protein, albumin, parathyroid hormone, and calculated free and bioavailable 25( OH )D. Weighted Cox proportional hazards models were used to examine their associations with CVD risk. Although vitamin D-binding protein and total, free, and bioavailable 25( OH )D were not significantly associated with CVD risk in black or white women, a significant positive association between parathyroid hormone and CVD risk persisted in white women (hazard ratio comparing the highest quartile with the lowest, 1.37; 95% CI , 1.06-1.77) but not in black women (hazard ratio comparing the highest quartile with the lowest, 1.12; 95% CI, 0.79-1.58), independent of total, free, and bioavailable 25( OH )D or vitamin D-binding protein. Conclusions Circulating levels of vitamin D biomarkers are not related to CVD risk in either white or black women. Higher parathyroid hormone levels may be an independent risk factor for CVD in white women.
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Higher Lipophilic Index Indicates Higher Risk of Coronary Heart Disease in Postmenopausal Women.
Liu, Q, Lichtenstein, AH, Matthan, NR, Howe, CJ, Allison, MA, Howard, BV, Martin, LW, Valdiviezo, C, Manson, JE, Liu, S, et al
Lipids. 2017;(8):687-702
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Abstract
Fatty acids (FAs) are essential components of cell membranes and play an integral role in membrane fluidity. The lipophilic index [LI, defined as the sum of the products between FA levels and melting points (°C), divided by the total amount of FA: [Formula: see text]] is thought to reflect membrane and lipoprotein fluidity and may be associated with the risk of coronary heart disease (CHD). Therefore, we examined the associations of dietary and plasma phospholipid (PL) LI with CHD risk among postmenopausal women. We determined dietary LI for the cohort with completed baseline food frequency questionnaires and free of prevalent cardiovascular diseases in the Women's Health Initiative (WHI) observational study (N = 85,563). We additionally determined plasma PL LI in a matched case-control study (N = 2428) nested within the WHI observational cohort study. Cox proportional hazard regression and multivariable conditional logistic regression were used to calculate HRs/ORs for CHD risk between quartiles of LI after adjusting for potential sources of confounding and selection bias. Higher dietary LI in the cohort study and plasma PL LI in the case-control study were significantly associated with increased risk of CHD: HR = 1.18 (95% CI 1.07-1.31, P for trend <0.01) and OR = 1.76 (95% CI 1.33-2.33, P for trend <0.01) comparing extreme quartiles and adjusting for potential confounders. These associations still persisted after adjusting for the polyunsaturated to saturated fat ratio. Our study indicated that higher LI based on either dietary or plasma measurements, representing higher FA lipophilicity, was associated with elevated risk of CHD among postmenopausal women.
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Serum 25-hydroxyvitamin D concentrations in relation to cardiometabolic risk factors and metabolic syndrome in postmenopausal women.
Chacko, SA, Song, Y, Manson, JE, Van Horn, L, Eaton, C, Martin, LW, McTiernan, A, Curb, JD, Wylie-Rosett, J, Phillips, LS, et al
The American journal of clinical nutrition. 2011;(1):209-17
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Abstract
BACKGROUND Low concentrations of serum 25-hydroxyvitamin D [25(OH)D] may be associated with cardiometabolic disorders; however, little is known about their relation to intermediate metabolic and lipid markers. OBJECTIVE We investigated the relation of serum 25(OH)D concentrations to fasting insulin, glucose, dyslipidemia, adiposity, and prevalent metabolic syndrome. DESIGN We conducted this cross-sectional analysis in 292 postmenopausal women aged 50-79 y in the Women's Health Initiative Calcium-Vitamin D (WHI-CaD) trial. Data were collected from 3 nested case-control studies that measured baseline serum 25(OH)D concentrations. Inverse probability weighting was used to approximate parameter estimates for the WHI-CaD population. RESULTS In weighted linear regression models adjusted for age, race-ethnicity, month of blood draw, region, case-control status, smoking, alcohol, physical activity, and history of cardiometabolic risk factors, there was an inverse association of serum 25(OH)D with adiposity [body mass index (BMI): β = -1.12 ± 0.30, P = 0.0002; waist circumference: β = -3.57 ± 0.49, P < 0.0001; waist-hip ratio: β = -0.01 ± 0.002, P < 0.0001], triglycerides (β = -0.10 ± 0.02, P < 0.0001), and triglyceride:HDL-cholesterol ratio (β = -0.11 ± 0.03, P = 0.0003). The multivariable-adjusted odds ratio for metabolic syndrome for the highest (≥52 nmol/L) compared with the lowest (<35 nmol/L) tertile of serum 25(OH)D concentrations was 0.28 (95% CI: 0.14, 0.56). Significant associations remained after adjustment for BMI. We observed no significant associations with LDL cholesterol, HDL cholesterol, insulin, glucose, homeostatic model assessment of insulin resistance (HOMA-IR), or homeostatic model assessment of β cell function (HOMA-β). CONCLUSION Higher serum 25(OH)D concentrations may be inversely associated with adiposity, triglycerides, triglyceride:HDL-cholesterol ratio, and metabolic syndrome but are not associated with LDL and HDL cholesterol, insulin, glucose, HOMA-IR, or HOMA-β in postmenopausal women. This trial was registered at clinicaltrials.gov as NCT00000611.