Author(s): Berg G, Kohlmeier L, Brenner H
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Abstract OBJECTIVE: Antioxidants, in particular carotenoids, may influence the risk for cardiovascular disease. This study investigates the influence of oral contraceptives (OC) on the serum concentration of beta-carotene, which may in turn affect the risk of cardiovascular diseases due to its antioxidative impact. DESIGN: Cross-sectional epidemiologic study. Examinations included a detailed questionnaire on medical history and lifestyle factors, a 7 day food record, and blood samples. SETTING: National health and nutrition survey among healthy people living in private homes in West Germany in 1987-1988. SUBJECTS: Nonpregnant and nonlactating women aged 18-44 (n = 610). RESULTS: Overall, the use of OC was negatively associated with serum beta-carotene concentration in bi- and multivariable analyses after adjustment for age, smoking, alcohol consumption, dietary intake of beta-carotene, use of vitamin supplements, body mass index, pregnancies, and serum concentrations of total triglyceride and cholesterol. A strong interaction between OC use and age on beta-carotene concentration was observed. While no relationship between OC use and serum beta-carotene was seen in the youngest age-group (18-24 y), there was a modest but significant negative association between OC use and beta-carotene levels among 25-34 y old women. The use of OC was associated with a strong decrease in beta-carotene levels among 35-44 y old women. The interaction between OC use and age could partly be explained by age dependent use of OC with higher estrogen content. CONCLUSIONS: OC use seems to be strongly related to serum beta-carotene levels, particularly among women above the age of 35. Further studies are needed to clarify the underlying mechanisms of this association and its implications for health risks of OC use. PIP: Beta-carotene, a provitamin with antioxidant effects, may substantially reduce the risk of coronary artery disease and acute myocardial infarction. A cross-sectional epidemiologic study involving 610 West German women 18-44 years of age indicates that oral contraceptive (OC) use has a negative impact on serum levels of beta-carotene. 195 respondents (32\%) were current OC users, 322 (53\%) were past users, and 91 (15\%) had never used OCs. Median serum beta-carotene levels were significantly lower in current OC users (25.1 mcg/dl) than in past (32.5 mcg/dl) and never users (31.2 mcg/dl). The percentage of women with beta-carotene levels below the desirable value of 21.5 mcg/dl was significantly higher in the current OC use group (34\%) than in the 2 other groups combined (21\%), yielding an overall odds ratio (OR) of 1.9 (95\% confidence interval, 1.3-2.8). The strength of the association between OC use and decreased beta-carotene increased with age (OR of 1.5 for women 18-24 years, 1.9 for those 25-34 years, and 3.4 for 35-44-year old women). In addition, the decrease of beta-carotene was larger for OCs containing 50 mcg of ethinyl estradiol than for low-dose formulations. Also observed were significant associations between serum beta-carotene levels and smoking, alcohol intake, body mass index, triglycerides, nutrient intake, and total cholesterol levels. Although further studies are required to identify the mechanisms underlying the OC-beta-carotene association and define its implications for women's health, OC users should be advised to consume vegetables rich in beta-carotene.
This article was published in Eur J Clin Nutr
and referenced in Primary Healthcare: Open Access