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Relationship between dietary carbohydrates intake and circulating sex hormone-binding globulin levels in postmenopausal women.
Huang, M, Liu, J, Lin, X, Goto, A, Song, Y, Tinker, LF, Chan, KK, Liu, S
Journal of diabetes. 2018;(6):467-477
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Abstract
BACKGROUND Low circulating levels of sex hormone-binding globulin (SHBG) have been shown to be a direct and strong risk factor for type 2 diabetes, cardiovascular diseases, and hormone-dependent cancers, although the relationship between various aspects of dietary carbohydrates and SHBG levels remains unexplored in population studies. METHODS Among postmenopausal women with available SHBG measurements at baseline (n = 11 159) in the Women's Health Initiative, a comprehensive assessment was conducted of total dietary carbohydrates, glycemic load (GL), glycemic index (GI), fiber, sugar, and various carbohydrate-abundant foods in relation to circulating SHBG levels using multiple linear regressions adjusting for potential covariates. Linear trend was tested across quartiles of dietary variables. Benjamini and Hochberg's procedure was used to calculate the false discovery rate for multiple comparisons. RESULTS Higher dietary GL and GI (both based on total and available carbohydrates) and a higher intake of sugar and sugar-sweetened beverages were associated with lower circulating SHBG concentrations (all P trend < 0.05; Q -values = 0.04,0.01, 0.07, 0.10, 0.01, and <0.0001, respectively). In contrast, women with a greater intake of dietary fiber tended to have elevated SHBG levels (P trend = 0.01, Q -value = 0.04). There was no significant association between total carbohydrates or other carbohydrate-abundant foods and SHBG concentrations. CONCLUSIONS The findings suggest that low GL or GI diets with low sugar and high fiber content may be associated with higher serum SHBG concentrations among postmenopausal women. Future studies investigating whether lower GL or GI diets increase SHBG concentrations are warranted.
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Effects of a low-fat dietary intervention on glucose, insulin, and insulin resistance in the Women's Health Initiative (WHI) Dietary Modification trial.
Shikany, JM, Margolis, KL, Pettinger, M, Jackson, RD, Limacher, MC, Liu, S, Phillips, LS, Tinker, LF
The American journal of clinical nutrition. 2011;(1):75-85
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Abstract
BACKGROUND Glycemic effects of the Women's Health Initiative (WHI) low-fat dietary intervention are unknown. OBJECTIVE Our objective was to analyze the effects of the WHI low-fat dietary intervention on serum glucose and insulin and insulin resistance up to 6 y after random assignment. DESIGN Postmenopausal WHI Dietary Modification trial intervention (DM-I) and comparison (DM-C) participants with blood measures at least at baseline and year 1 (n = 2263) were included. Anthropometric measures, dietary assessments, serum glucose and insulin concentrations, homeostasis model assessment of insulin resistance (HOMA-IR) measures, and quantitative insulin sensitivity check index (QUICKI) values were obtained at baseline, year 1, year 3, and year 6. Changes in measures were compared between groups at years 1, 3, and 6 overall and within stratified analyses. RESULTS Mean (±SD) differences in changes at year 1 between the DM-I and DM-C groups were as follows: glucose, -1.7 ± 17.9 mg/dL; insulin, -0.7 ± 5.1 μIU/mL; HOMA-IR, -0.2 ± 1.9; and QUICKI, 0.004 ± 0.019 (all P < 0.05). Similar findings resulted from repeated-measures analyses comparing the intervention and comparison groups over the 6 y. Whereas normoglycemic women at baseline had a decrease in glucose at year 1 that was 1.9 ± 17.2 mg/dL greater in the DM-I than in the DM-C group, diabetic women had an increase in glucose that was 7.9 ± 20.3 mg/dL greater in the DM-I than in the DM-C group (P for interaction <0.001). CONCLUSIONS A low-fat diet was not significantly associated with adverse glycemic effects up to 6 y after random assignment in postmenopausal women. However, diabetic women experienced adverse glycemic effects of the low-fat diet. This trial is registered at clinicaltrials.gov as NCT00000611.