Reproductive, menstrual, and medical risk factors for endometrial cancer: results from a case-control study.

OBJECTIVE: Our objective was to evaluate the risk for endometrial cancer in relation to reproductive, menstrual, and medical factors. STUDY DESIGN: A case-control study of 405 endometrial cancer cases and 297 population controls in five areas of the United States enabled risk to be evaluated. RESULTS: A major risk factor was the absence of a prior pregnancy (relative risk 2.8, 95% confidence interval 1.7 to 4.6). The protective effect of pregnancy appeared to reflect the influence of term births, because spontaneous and induced abortions were unrelated to risk. Among nulliparous women infertility was a significant risk factor, with women having sought medical advice having nearly eight times the risk of those without difficulty conceiving. After adjustment for other reproductive characteristics, age at first birth and duration of breast-feeding were not related to risk. CONCLUSIONS: Elevated risks were found for subjects reporting early ages at menarche (relative risk 2.4 for ages < 12 vs > or = 15) and longer days of flow (relative risk 1.9 for > or = 7 vs < 4 days), but there was no relationship with late ages at natural menopause. Height was not associated with risk, but there was a significant relation to weight, with the risk for 200 versus < 125 pounds being 7.2 (95% confidence interval 3.9 to 13.3). After adjustment for weight and other factors, histories of hypertension and gallbladder disease were not significantly related to risk, but an effect of diabetes persisted (relative risk 2.0, 95% confidence interval 1.1 to 3.6). Hirsutism developing at older ages was also significantly related (relative risk 2.0, 95% confidence interval 1.2 to 3.4).

Field issues for the plan and operation of the laboratory component of the Third National Health and Nutrition Examination Survey.

The design of the laboratory component of a mobile examination survey such as the National Health and Nutrition Examination Survey requires that the physical limitation of the mobile examination center be balanced against the requirements of the laboratory analyses needed to fulfill the goals of the survey. In order to include an analysis in the survey, the scientific merit of the laboratory test must be established and a consensus must be reached on the appropriateness of the technology for the six years of the survey. The public health importance of the analysis and the subsequent results are also evaluated before inclusion into the laboratory protocol. Finally, the feasibility of incorporating the analysis into the protocol is reviewed. The laboratory component of NHANES III is discussed, addressing these points with descriptions of the reasons for inclusion and exclusion of key analytes.

Oral contraceptive use, human papillomavirus infection, and risk of early cytological abnormalities of the cervix.

Oral contraceptive (OC) use was examined as a risk factor for cytological abnormalities of the cervix among 1964 women receiving Papanicolaou smears at three hospitals in the Washington, D.C., area. A single pathologist classified cytological results from all women as normal (n = 1423), atypia (n = 314), low grade squamous intraepithelial lesion (SIL; n = 208), or high grade SIL (n = 19). Women in each of the three abnormal groups were compared to women with normal cytological diagnoses. A subset of 579 patients, including most of the women with low or high grade SIL and a matched group of controls, was tested for human papillomavirus (HPV) by type-specific Southern blot hybridization to examine the effects of OC use while taking into account the effects of HPV infection. OC use was found to be unrelated to risk of atypia or low grade SIL but was associated with an elevated risk of high grade SIL that increased with longer duration of use (relative risk = 4.6, 95% confidence interval = 1.1-18.1 for greater than or equal to 5 years of use). HPV infection was associated, as expected, with risk of low and high grade SIL but not with atypia. Taking the HPV results into consideration did not alter the OC findings. There was no evidence that OC use synergistically increased the risk of cervical neoplasia among HPV-infected women, although small numbers prevented a reliable evaluation for high grade SIL. OC use did appear to increase the detection of HPV types 16/18, but the etiological importance of this finding is unclear.

Biochemical epidemiology of cervical neoplasia: measuring cigarette smoke constituents in the cervix.

In preparation for an epidemiological investigation of cigarette smoking and cervical neoplasia, we studied methods of measuring cervical exposure to tobacco smoke. The measurement of cotinine in cervical flushes by radioimmunoassay proved to be highly accurate in distinguishing smokers from nonsmokers, achieving 100% sensitivity and 97% specificity. In most subjects, quantitative levels of cervical cotinine and nicotine mirrored recent smoking intensity. Some of the apparent exceptions may have resulted from metabolic/secretory traits of the subjects. If so, the biochemical measurement of smoke constituents in the cervix might prove more valuable for epidemiological studies of cervical neoplasia than data on current smoking behavior collected by interview.