Search

To characterize further the relationship between smoking history and Parkinson disease (PD) risk by considering temporal and qualitative features of smoking exposure, including duration, average intensity, and recentness, as well as the relative importance of smoking during different periods of life.

Two recent studies suggest that the risk of ALS is increased among Gulf War veterans. It is not known whether military service outside of the Gulf War is associated with increased risk of ALS.

Only a few prospective studies have examined the relationship between the frequency of cigarette smoking and the incidence of diabetes mellitus. The purpose of this study was to determine whether greater frequency of cigarette smoking accelerated the development of diabetes mellitus, and whether quitting reversed the effect.

Licensed hospitals usually maintain a discharge diagnoses index, which provides an inexpensive tool for the surveillance of birth defects diagnosed shortly after birth. Government agencies in several states routinely use discharge diagnoses for this purpose. To evaluate the completeness of the discharge diagnoses, the authors compared birth defects noted in the discharge diagnoses with those noted anywhere in the hospital birth record in a cohort of 3,421 infants born to US Army veterans from 1966 to 1986. In this cohort, 237 birth defect cases were documented in hospital birth records, and 49% of those cases were missed in the discharge diagnoses (28% of major defect cases and 66% of minor defect cases). The extent of missed defects varied greatly by organ system and by specific defect. Significant predictors of a missed defect were the presence of multiple defects, female sex, and western region of birth. The underascertainment of defects in the discharge diagnoses should be considered in the development and operation of surveillance systems using this source of data.

Characteristics of nonrespondents, respondents who were easy to locate, and respondents who were hard to locate were examined with the use of data from a telephone health survey of male, US Army, Vietnam-era veterans. Of 17,867 eligible men discharged from active military duty in the late 1960s and early 1970s, 15,288 (86%) were successfully located and interviewed during 1985-1986. Veterans who could not be located were more likely than respondents to possess baseline characteristics predictive of increased mortality. In contrast, subjects who were located but refused to be interviewed were similar to respondents. Among veterans who were interviewed, those who were hardest to locate had the highest prevalence of known risk factors for diminished health status and reported many health problems with higher relative frequencies than respondents who were easier to locate. Odds ratios comparing the prevalence of each of 11 health outcomes in men who had served in Vietnam with that in men who had served elsewhere did not vary appreciably by intensity of follow-up. In particular, the subgroup of respondents that was located and interviewed within 2 weeks of initiation of follow-up (comprising 25% of all respondents) produced odds ratios for 10 of the 11 outcomes that were not appreciably different from odds ratios based on all respondents.

A family history of breast cancer potentially identifies women at high risk for whom mammography may be especially valuable. The authors examined the association of fatal breast cancer and family history in a large, prospective study of US adults. After 6 years of follow-up, 880 cases of fatal breast cancer were observed in a cohort of 604,412 women who were cancer free at interview in 1982. Cox proportional hazards modeling found that a family history of breast cancer in a mother or sister was significantly related to fatal breast cancer risk (rate ratio = 1.59, 95% confidence interval (CI) 1.29-1.95). The association was greatly modified by age; the rate ratio was 4.91 (95% CI 1.39-17.3) in women aged < 40 years at enrollment compared with 1.28 (95% CI 0.78-2.11) in women aged > or = 70 years. Among young (aged < 50 years) women, the risk associated with a positive family history was greatest if the relative was also young at the time of diagnosis (rate ratio = 5.22, 95% CI 3.00-9.11). These associations were not altered in multivariate analyses controlling for known breast cancer risk factors. In the authors' data, family history is strongly predictive of early fatal breast cancer, particularly when the disease is diagnosed before age 50 in the relative. Women with a family history of early breast cancer should receive special instructions regarding mammography and early detection.

Rohrer's ponderal index in newborns (birth weight/heights x 100) has been used as an indicator of fetal growth status, especially to assess asymmetrical intrauterine growth retardation. Because low birth weight and intrauterine growth retardation tend to recur in sibships, we examined patterns of sibling correlation in the ponderal index in 795 live term (greater than or equal to 37 weeks) singleton sibling pairs without birth defects born between 1966 and 1986 and fathered by male US Army veterans participating in a nationwide health study. Data on birth weight, length, gestational age, and other maternal and infant health characteristics were abstracted from hospital-of-birth medical records. The correlation coefficient of ponderal index in sib pairs was 0.24 (p less than 0.001). Compared with 627 infants who had a prior sib with a ponderal index between the 10th and 90th percentiles, 92 infants who had a prior sib with ponderal index less than the 10th percentile had a lower mean ponderal index and a higher proportion with ponderal index less than the 10th percentile (13.0% vs. 8.5%). On the other hand, 76 infants who had a prior sib with ponderal index greater than the 90th percentile had a higher mean ponderal index and higher proportion with ponderal index greater than the 90th percentile (17.1% vs. 10.2%). The clustering of ponderal index in siblings persisted after controlling for factors such as race, gender, maternal age, gravidity, year of birth, gestational age, pregnancy complications, and prior maternal illnesses. The findings point to the presence of genetic and/or maternal factors affecting the growth status of term newborn infants. The significance of the ponderal index needs to be examined in future genetic and epidemiologic studies of intrauterine growth.

The authors examined the relation between use of estrogen replacement therapy and ovarian cancer mortality in a large prospective mortality study of 240,073 peri- and postmenopausal women, none of whom had a prior history of cancer, hysterectomy, or ovarian surgery at enrollment in 1982. During 7 years of follow-up, 436 deaths from ovarian cancer occurred. Cox proportional hazard regression was used to adjust for other risk factors. Ever use of estrogen replacement therapy was associated with a rate ratio for fatal ovarian cancer of 1.15 (95% confidence interval (CI) 0.94-1.42). The mortality rate ratio increased with duration of use prior to entry to this study to 1.40 (95 CI% 0.92-2.11) with 6-10 years of use and 1.71 (95% CI 1.06-2.77) with > or = 11 years of use. The increase in mortality associated with > or = 6 years of use was observed in both current users (rate ratio (RR) = 1.72, 95% CI 1.01-2.90) and former users at study entry (RR = 1.48, 95% CI 0.99-2.22), relative to never users. Risk associated with use was not modified by any of the other risk factors. These data suggest that long-term use of estrogen replacement therapy may increase the risk of fatal ovarian cancer.

This paper reports the results of testing and using the National Death Index to ascertain vital status in the American Cancer Society's prospective cohort study, Cancer Prevention Study II. This cohort of over one million men and women, enrolled by volunteers in 1982, is one of the largest ever to be linked with the National Death Index. In a linkage of over 15,000 persons whose vital status through 1988 had been traced through manual follow-up, 93% of all known deaths were ascertained. Sensitivity varied by demographic factors (race, sex) and availability of identifying information (Social Security number, middle initial). When the Social Security number was available, 97% of known deaths were accurately identified. A computerized matching algorithm was used to minimize manual review of records. With this method, the authors were able efficiently and accurately to reject the many false-positive matches while maintaining a reasonable level of manual record review and death certificate acquisition, thus allowing for continued automated follow-up of this valuable cohort.

The mortality odds ratio computed with a decedent control series (ORD) and the mortality odds ratio obtained with a living control series (ORL) estimate the mortality rate ratio (RRM) under very different assumptions. The bias of the ORD as an estimate of RRM is a function of the mortality rates from other causes (those causes for which controls were selected) in the underlying exposed (E) and nonexposed (E) populations, while the bias of ORL as an estimate of RRM is a function of the prevalence of the study disease in the underlying E and E populations. The ORL closely estimates the RRM if the prevalence of the disease under study is small. If the study disease mortality rate is small relative to the other-causes mortality rate, the ORD closely estimates the cause-specific proportional mortality ratio.

The authors examined the association of fatal breast cancer and cigarette smoking in a large, prospective mortality study of US adults. After 6 years of follow-up, 880 cases of fatal breast cancer were observed in a cohort of 604,412 women who were cancer-free at interview in 1982. Cox proportional hazards modeling, adjusted for other risk factors, found that current smoking was significantly related to fatal breast cancer risk (adjusted rate ratio (RR) = 1.26, 95% confidence interval (CI) 1.05-1.50). A negative association was observed for former smokers, but this was not statistically significant (RR = 0.85, 95% CI 0.70-1.03). The association of current smoking with fatal breast cancer risk increased with increasing numbers of cigarettes per day and with total number of years smoked. For smokers of 40 or more cigarettes per day, the rate ratio was 1.74 (95% CI 1.15-2.62). The authors hypothesize that these results may be due to either a poorer prognosis among breast cancer cases who smoke or a delayed diagnosis among current smokers who do not receive mammograms as often as never or former smokers. Women who smoke should be targeted for breast cancer screening services.

Research needs in health effects assessment are discussed within the broad framework of a multidisciplinary approach. Approaches for comparing and analyzing data at all levels of biological organization are identified. These approaches should provide insights that will stimulate advances in the general art of risk assessment.