The influence of oral contraceptives and habitual physical activity on serum lipids in black adolescents and young women

The effects of oral contraceptive use and habitual physical activity on serum cholesterol and lipoproteins were studied in 37 black females ages 16 to 28 years over a 3-month period. By the third month of oral contraceptive use, high-density lipoprotein (HDL) levels were lower and the low-density lipoprotein (LDL) to HDL ratio and total serum cholesterol (T Chol) to HDL ratio were significantly higher in those receiving oral contraceptive with norgestrel. The level of physical activity had no significant effect on HDL levels. The active subjects had lower T Chol and HDL levels and a lower T Chol to HDL ratio at the end of 3 months. Subjects in the active-norethindrone group had lower T Chol to HDL ratios than those taking norgestrel. The nonactive norgestrel group had a continuous increase in their T Chol to HDL ratio over the 3-month period. These effects should be considered when counseling sexually active teenagers and when recommending an oral contraceptive.

Prevalence and trends in oral contraceptive use in premenopausal females ages 12-54 years, United States, 1971-80

Data from the second National Health and Nutrition Examination Survey (NHANES II) were analyzed to estimate the prevalence of oral contraceptive use in the United States, 1976-80. The overall unadjusted prevalence of oral contraceptive use was 16.7 per cent for premenopausal females ages 12-54 years (19.2 per cent for ages 15-44 years). Approximately 8.7 million females (95 per cent confidence interval, 6.9-10.5 million) were oral contraceptive users at the midpoint of NHANES II (March 1978). Comparison to the NHANES I, conducted in 1971-74, indicated a stable number of overall oral contraceptive users in the US population during the 1970s, with shifts in certain age groups: oral contraceptive use increased for females ages 12-19 years and decreased for females ages 20-49 years. The overall age-adjusted prevalences indicated a 2 per cent (95 per cent CI, 0.2-3.8 per cent) decline in oral contraceptive use from the early to the late 1970s. The NHANES provides comparative data and supports findings from another national survey showing a decrease in the per cent of females using oral contraceptives during 1973-82. Trends in oral contraceptive use are also presented by race, poverty level, rural-urban residence, marital status, and education level.

Oral contraceptives and cardiovascular disease: a critique of the epidemiologic studies

Observational study designs used to investigate the relationship of oral contraceptive use to the occurrence of venous thromboembolism, stroke, myocardial infarction, and cardiovascular death include case-control, cohort, and mortality statistics studies. This analysis catalogs the findings of each of these epidemiologic studies, its statistical significance, and its performance with regard to scientific methodologic standards. An association between current oral contraceptive use and incidence of venous thromboembolism without predisposition has been consistently observed in case-control and cohort studies. Associations are less consistent for various types of stroke and for myocardial infarction. Only the Royal College of General Practitioners study found a significantly elevated risk of cardiovascular death with oral contraceptive use. The majority of mortality statistics studies offer little support for a relationship between oral contraceptive use and cardiovascular events. Major systematic problems in the epidemiologic studies include potential for bias in the detection of cardiovascular events and differences in the prognostic susceptibility of compared groups. Bias in the ascertainment of drug exposure is an unresolved issue for most of the case-control studies. Because of possible biases arising from methodologic deficiencies in these epidemiologic studies, questions as to the validity of the observed associations between oral contraceptive use and cardiovascular events should remain.

Oral contraceptives and mortality from circulatory system diseases: an epidemiologic study in Taiwan

An epidemiological study on the association between oral contraceptive (OC) use and circulatory system disease (CSD) mortality undertaken in Taiwan by proxy interview of closest family members of 306 deceased cases, 305 deceased controls, and 611 healthy neighborhood controls indicated that the relative risk between the cases and health controls was 0.98 (0.62-1.54) and that between cases and health controls was 0.82 (0.56-1.21). Use of OC by Taiwanese women has not produced any overwhelming adverse effects on CSD mortality.

Oral contraceptives and the decline in mortality from circulatory disease

Many publications have claimed that oral contraceptives (OCs) are associated with an increased risk of circulatory disease, yet between the years 1962 and 1976, when OCs became widely used in the United Kingdom, death rates from circulatory disease in women of reproductive age fell steadily. This decreased mortality was greater in young women than in men of comparable age, and did not occur in older women. These data tend strongly to refute the belief that OCs are causative of circulatory disease. The possibility that the decreased mortality rate is due to a protective effect of OCs was examined. It was concluded that they could not be completely responsible, although a partial effect could not be ruled out with certainty. It is suggested that, when mortality trends are opposed to the results of case-control or cohort studies, serious doubts are cast on the conclusions about causal relationships.

Oral contraceptive use and diseases of the circulatory system in Taiwan: an analysis of mortality statistics

Whether or not increased prevalence of oral contraceptive use in developing countries is associated with increased morbidity and mortality from circulatory system diseases is a serious concern for health and family planning administrators. An analysis of Taiwan's mortality statistics to determine whether such an association existed was undertaken, taking advantage of the excellent vital statistics and medical care systems existing there. The analysis failed to demonstrate that death rates from circulatory system diseases among Taiwanese women of childbearing age have increased since the promotion of oral contraceptive use began in 1967. In fact, mortality from all forms of circulatory system diseases has generally declined since 1967 and the slopes of declines for females of childbearing age who were exposed to oral contraceptives were somewhat greater than those of males of the corresponding age groups.