American Journal of Epidemiology

Halloran, M.Elizabeth; Haber, Michael; Longini, Ira M.; Struchiner, Claudio J.

doi: 10.1093/oxfordjournals.aje.a115884pmid: 1899778

In 1915, Greenwood and Yule noted that for valid vaccine efficacy studies, exposure to infection in the vaccinated and the unvaccinated must be equal (Proc R Soc Med 1915;8(part 2):113–94). The direct effect of a vaccine, however, needs to be defined by the protection it confers given a specific amount of exposure to infection, not just a comparable exposure. In this paper, two classes of parameters are distinguished along lines differing from the conventional distinction between efficacy and effectiveness. Efficacy parameters attempt to control for exposure to infection and represent direct effects on individuals. Direct effectiveness parameters represent a mixture of direct effects on individuals and indirect effects in the population. Am J Epidemiol 1991; 133:323–31.

Stergachis, Andy; Scholes, Delia; Daling, Janet R.; Weiss, Noel S.; Chu, Joseph

doi: 10.1093/oxfordjournals.aje.a115885pmid: 1822668

The association between maternal smoking and the occurrence of tubal pregnancy was evaluated in a population-based case-control study of members of the Group Health Cooperative of Puget Sound, Seattle, Washington. Women hospitalized with tubal pregnancy from October 1981 through September 1986 (n = 274) were compared with reproductive-age women who were at risk of becoming pregnant during the same time period (n = 727). The relative risk of tubal pregnancy associated with ever having smoked cigarettes was 1.3 (95% confidence interval (Cl) 1.0–1.8). Compared with women who had never smoked, those who smoked at the time of conception had a 40% increase in the risk of tubal pregnancy (95% Cl 1.0–2.0). These results support earlier epidemicdogic and noneptdemiologic reports of a greater risk of tubal pregnancy associated with current or recent maternal cigarette smoking. Am J Epidemiol 1991; 133:332–7.

Ahlborg, Gunnar; Bodin, Lennart

doi: 10.1093/oxfordjournals.aje.a115886pmid: 1994696

Among 4,687 women undergoing prenatal care in Örebro County, Sweden, from October 1980 to June 1983, 678 nonsmokers reported passive exposure to tobacco smoke. Of these women, 267 had been passively exposed at work, and the risk ratio (RR) for intrauterine death (spontaneous abortion or stillbirth) among these pregnancies was increased to 1.53 (95% confidence interval (Cl) 0.98–2.38) compared with pregnancies of unexposed working women. This could not be explained by age, previous spontaneous abortion, educational level, planning of pregnancy, or alcohol use. The effect was confined to first-trimester fetal loss (adjusted RR = 2.16,95% Cl 1.23–3.81), while active smoking was associated with intrauterine death after the first trimester. Passive exposure in the workplace was weakly associated with preterm birth (<37 weeks) but not with low birth weight (<2,500 g) among full-term livebirths. Active smoking clearly increased the risk of both of these outcomes. However, passive exposure in the home only did not seem to affect pregnancy outcome. The lack of quantitative exposure data points to the need for more research before passive exposure to tobacco smoke can be regarded as an established hazard to fetal development and survival. Am J Epidemiol 1991;133:338–47.

Samet, Jonathan M.

doi: 10.1093/oxfordjournals.aje.a115887pmid: 1994697

Hakim, Rosemarie B.; Stewart, Walter F.; Canner, Joseph K.; Tielsch, James M.

doi: 10.1093/oxfordjournals.aje.a115888pmid: 1994698

The authors conducted a population-based case-control study to investigate the association between strabismus and parental occupational lead exposure. Cases were children diagnosed with nonrestrictive strabismus between 1985 and 1986 at Baltimore, Maryland-area pediatric ophthalmology practices and clinics (n = 377). Controls were matched for age and hospital of birth (n = 377). Jobs held by parents were assessed for lead exposure by industrial hygienists. The time window for lead exposure was defined as the period from conception through age 9 months. The unadjusted odds ratio for maternal lead exposure and the esotropic form of strabismus was 2.6 (95% confidence interval (Cl) 0.4–27). Unadjusted odds ratios for paternal occupational lead exposure and esotropia were 1.0 (95% Cl 0.5–2.1) for low exposure, 2.1 (95– Cl 0.9–5.3) for moderate exposure, and 1.2 (95% Cl 0.4–3.3) for high exposure. The study results suggest the possibility of a weak association between paternal lead exposure and strabismus in offspring. Am J Epidemiol 1991 ;133:351–6.

Acquavella, John F.; Owen, Cynthia V.; Bird, Michael G.; Yarborough, Charles M.; Lynch, Jeremiah

doi: 10.1093/oxfordjournals.aje.a115889pmid: 1994699

To assess potential etiologic factors among a population of Texas polypropylene workers previously found to have an excess of colorectal cancer (concentrated among mechanical and process workers), the authors conducted an adenomatous polyp case-control study. Cases (n = 24) were workers found to have adenomatous polyps during a company-sponsored colorectal cancer screening program, while controls (n = 72) were workers found to be free of polyps. Exposure assessment utilized a thorough industrial hygiene and toxicologic review of operations in conjunction with work activity interviews of cases and controls to develop chemical-specific exposure scores weighted by time, exposure level, and frequency of exposure. Stratified analyses and logistic regression found that cases tended to have higher exposure to pre-extrusion polymer plus additives (odds ratio (OR) = 2.6, 90% confidence interval (Cl) 1.1–6.3) and higher exposure to certain finishing additives (OR = 4.8, 90% Cl 1.5–15.3). Analyses by job category or area of the plant did not indicate additional risk factors. The exposures identified in this study are discussed in light of the available toxicologic data on these and related compounds. Trie need for confirmatory experimental and eptdemiologic studies is noted. Am J Epidemiol 1991;133:357–67.

Gardner, John W.; Schuman, Katharina L.; Slattery, Martha L.; Sanborn, Jill S.; Abbott, Thomas M.; Overall, James C.

doi: 10.1093/oxfordjournals.aje.a115890pmid: 1994700

The association between cervical carcinoma and vaginal douching was examined in a population-based case-control study conducted in the low-risk population of Utah between 1984 and 1987. The authors compared 266 cases of in situ and invasive cervical carcinoma with 408 group-matched controls by vaginal douching behavior, controlled for age, lifetime number of sex partners, cigarette smoking history, religious activity, and educational level. Essentially no association was found in women who douched once per week or less, but in those who douched more than once per week, a consistent relation was demonstrated (adjusted odds ratio = 4.7, 95% confidence interval 1.9–11). Few differences were found with type of douching preparation used. The authors hypothesize that frequent douching alters the vaginal chemical environment, making the cervix more susceptible to pathologic change. Am J Epidemiol 1991; 133:368–75.

Friedman, Gary D.; Fireman, Bruce H.

doi: 10.1093/oxfordjournals.aje.a115891pmid: 1994701

A previous report that the leukocyte count was related to mortality from cancer was evaluated in two large groups of multiphasic health examinees in the San Francisco Bay area, California—a cohort of about 25,000 persons followed up for mortality and a cohort of about 160,000 persons followed up for cancer incidence between 1964 and 1980. The leukocyte count was related to mortality from all cancers, smoking-related cancers, and cancers that were not smoking-related, but it was not related to cancer mortality in nonsmokers. The leukocyte count showed an association with the incidence of smoking-related cancers that was only partially removed by analytical control for smoking. It was only slightly, if at all, related to the incidence of not-smoking-related cancers and to the incidence of all cancers among nonsmokers. The relation of the leukocyte count to cancer mortality appears to be due to its close association with cigarette smoking, which raises the incidence of certain cancers and can hasten death attributed to cancer. Am J Epidemiol 1991 ;133:376–80.

Kostraba, Jill N.; Klein, Ronald; Dorman, Janice S.; Becker, Dorothy J.; Drash, Allan L.; Maser, Raelene E.; Orchard, Trevor J.

doi: 10.1093/oxfordjournals.aje.a115892pmid: 1994702

The roles of potential risk factors for background and proliferative retinopathy were evaluated in cross-sectional analyses from the Epidemiology of Diabetes Complications Study, Pittsburgh, Pennsylvania. This report presents results from the 657 insulin-dependent diabetic participants seen at the baseline examination (1986–1988). The presence of and severity of retinopathy were judged from stereoscopic photographs of three views of the ocular fundus using the modified Airlie House classification system. Fifty-three percent of the participants had background retinopathy, and 31% had proliferative retinopathy. Logistic regression analyses showed that among participants aged less than 18 years, those with background retinopathy were older and had higher levels of glycosylated hemoglobin compared with those without retinopathy. In the 18–29-year age group, participants with background retinopathy had a longer duration of diabetes, higher tow density lipoprotein (LDL) cholesterol levels, and lower high density lipoprotein cholesterol levels and were more likely to have mtcroalbuminuria compared with those without retinopathy. Participants aged 18–29 years with proliferative retinopathy had a longer duration of diabetes, higher diastolic Wood pressure, and higher fibrinogen and LDL cholesterol levels than those with background retinopathy. In the age group ≥30 years, diabetes duration, diastolic blood pressure, and fibrinogen, LDL cholesterol, and triglyceride levels were increased in participants with proliferative retinopathy versus those with background retinopathy. In a multivariate model of proliferative retinopathy, controlling for concurrent renal disease weakened the influence of blood pressure, fibrinogen, triglycerides, and LDL cholesterol and improved the overall fit of the model. These results suggest that diabetic nephropathy may contribute to the development of proliferative (but not background) retinopathy by increasing Wood pressure and fibrinogen, by altering the lipoprotein profile, and possibly through other mechanisms. Am J Epidemiol 1991 ;133:381–91.

Gellin, Bruce G.; Broome, Claire V.; Bibb, William F.; Weaver, Robert E.; Gaventa, Suzanne; Mascola, Laurene; ,

doi: 10.1093/oxfordjournals.aje.a115893pmid: 1899779

To determine the morbidity and mortality due to listenosis in the United States, the authors undertook an active surveillance project in 1986 to identify all cases in which Listeria monocytogenes was isolated from cultures of ordinarily sterile sites in a population of 34 million persons. The authors estimated that at least 1,700 cases of listeriosis and 450 deaths occurred in the United States in 1986; 27% of these cases occurred in pregnant women, with 22% of pennatal cases resulting in stillbirths or neonatal deaths. The risk of listeriosis in adults (0.5 per 100,000 population) was similar in all regions studied; the incidence of perinatal listeriosis was three times higher in Los Angeles County, California, than in the other areas (24.3/100,000 live births vs. 7.8/ 100,000 live births). Geographic variation may have resulted from underdiagnosis of perinatal listeriosis in five of the study areas. Multilocus electrophoretic enzyme typing was useful for elucidating the molecular epidemiology of L. monocytogeneS; pennatal listeriosis was significantly associated with one group of related strains. Multilocus electrophoretic enzyme typing also identified three clusters representing possible common-source outbreaks. These findings document the substantial morbidity due to listeriosis in the United States; to the extent that sporadic listeriosis is foodbome, this morbidity could be reduced by appropriate preventive measures, particularly in persons known to be at increased risk of infection. Am J Epidemiol 1991 133:392–401.