Serum Retinol and Carotenoids in Association with Biomarkers of Insulin Resistance among Premenopausal Women.
OBJECTIVE
The aim of this study was to investigate how serum retinol and carotenoids (β-carotene,β-cryptoxanthin, lutein/zeaxanthin, lycopene) are associated with biomarkers of insulin resistance.


METHODS
The BioCycle Study (2005-2007) is a prospective cohort of 259 healthy premenopausal women. Fasting serum samples were collected at up to sixteen clinic visits, from which retinol, carotenoids, insulin, glucose, and sex hormone-binding globulin (SHBG) were measured. Insulin resistance was estimated by the homeostasis model assessment (HOMA-IR). Linear mixed models were used to determine associations adjusting for age, race, body mass index (BMI), education, smoking, physical activity, triglycerides, and energy intake.


RESULTS
Retinol was positively associated with HOMA-IR (β= 0.19 (95% CI: 0.07, 0.32)) units per ug/mL increase in retinol; the relationship was driven by insulin (β= 0.20 (95% CI: 0.08, 0.31)). Retinol was inversely associated with SHBG (β= -0.22 (95% CI: -0.28, -0.16)). Although no significant associations were found between serum carotenoids and HOMA-IR,β-carotene was positively associated with SHBG andβ-cryptoxanthin inversely with fasting plasma glucose.


CONCLUSIONS
Results indicate a possible role for serum retinol in the pathogenesis of type 2 diabetes. However, they do not support a strong association between individual or total serum carotenoids and insulin resistance.
Epidemiology Branch, Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, USA ; Center for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
Stacy A
SA
Blondin
Edwina H
EH
Yeung
Sunni L
SL
Mumford
Cuilin
C
Zhang
Richard W
RW
Browne
Jean
J
Wactawski-Wende
Enrique F
EF
Schisterman