Tracing a Path to the Past: Exploring the Use of Commercial Credit Reporting Data to Construct Residential Histories for Epidemiologic Studies of Environmental Exposures.

Large-scale environmental epidemiologic studies often rely on exposure estimates based on linkage to residential addresses. This approach, however, is limited by the lack of residential histories typically available for study participants. Our objective was to evaluate the feasibility of using address data from LexisNexis (a division of RELX, Inc., Dayton, Ohio), a commercially available credit reporting company, to construct residential histories for participants in the California Teachers Study (CTS), a prospective cohort study initiated in 1995-1996 to study breast cancer (n = 133,479). We evaluated the degree to which LexisNexis could provide retrospective addresses prior to study enrollment, as well as the concordance with existing prospective CTS addresses ascertained at the time of the completion of 4 self-administered questionnaires. For approximately 80% of CTS participants, LexisNexis provided at least 1 retrospective address, including nearly 25,000 addresses completely encompassed by time periods prior to enrollment. This approach more than doubled the proportion of the study population for whom we had an address of residence during the childbearing years-an important window of susceptibility for breast cancer risk. While overall concordance between the prospective addresses contained in these 2 data sources was good (85%), it was diminished among black women and women under the age of 40 years.

Adverse birth outcomes and maternal complications in licensed cosmetologists and manicurists in California.

PURPOSE: Due to concerns around occupational chemical exposures, this study sought to examine whether women working as cosmetologists (providing hair and nail care services) and manicurists (providing only nail care services) have an elevated risk for adverse pregnancy outcomes. METHODS: In this population-based retrospective study of cosmetologists and manicurists in California, we linked cosmetology licensee and birth registry files to identify births during 1996-2009. We compared outcomes among cosmetologists and manicurists to those of the general female population and to women from other industries. We also conducted restricted analyses for Vietnamese women, who comprise a significant proportion of the workforce. RESULTS: There was little evidence of increased risk for adverse birth outcomes, but we observed an association for small for gestational age (SGA) among Vietnamese manicurists (OR 1.39; 95 % CI 1.08-1.78) and cosmetologists (OR 1.40; 95 % CI 1.08-1.83) when compared to other working women. Some maternal complications were observed, notably an increased risk for gestational diabetes (OR 1.28; 95 % CI 1.10-1.50 for manicurists; OR 1.19; 95 % CI 1.07-1.33 for cosmetologists) compared with the general population, which further elevated when restricted to Vietnamese workers (OR 1.59; 95 % CI 1.20-2.11 for manicurists; OR 1.49; 95 % CI 1.04-2.11 for cosmetologists). Additionally, we observed an association for placentia previa among manicurists (OR 1.46; 95 % CI 1.08-1.97) and cosmetologists (OR 1.22; 95 % CI 1.02-1.46) compared with the general population. CONCLUSIONS: Women in the nail and hair care industry may be potentially at increased risk for some maternal complications, although further research is warranted. Vietnamese workers may also have increased risk for SGA.

Birth size and breast cancer risk among young California-born women.

OBJECTIVE: Evaluate the risk of breast cancer associated with birth size among young California-born women. METHODS: Invasive breast cancer cases diagnosed 1988-2004 among women born in California during the 1960s were identified from the California Cancer Registry. Breast cancer cases (n = 3,712) were linked to their California birth records. Controls (n = 8,615) were randomly selected from California birth records for women, frequency matched to cases by birth year. Odds ratios (ORs) and 95% confidence intervals (95% CI) were estimated from unconditional logistic regression. RESULTS: The adjusted OR for breast cancer associated with the highest category of birth weight (≥4,000 g) was 1.12 (95% CI 0.89-1.41), p-trend = 0.02. The adjusted OR for the highest category of birth length (>20 inches) was 1.13 (95% CI 1.02-1.25), p-trend = 0.02. These relationships appeared to be confined to cases with estrogen receptor positive (ER+) tumors (p-trend ≤0.01) or progesterone receptor positive (PR+) tumors (p-trend ≤0.02). No significant associations were found among cases with ER or PR negative tumors. CONCLUSIONS: Our results confirm previous findings of elevated breast cancer risk associated with increases in birth size. These risks may be confined to ER+ and PR+ tumors, highlighting the potential mechanistic role of sex steroid hormonal pathways.

Cancer incidence in female cosmetologists and manicurists in California, 1988-2005.

Health concerns have been pronounced for cosmetologists and manicurists, who are exposed daily to cosmetic products containing known or suspected human carcinogens and endocrine disruptors. In this retrospective cohort study, the authors used probabilistic record linkage between California's statewide cosmetology licensee and cancer surveillance files to identify newly diagnosed invasive cancers among female workforce members during 1988-2005. Rate ratios and 95% confidence intervals for cancer among workforce members compared with the general female population in California were estimated via Poisson regression. For comparison, site-specific proportional incidence ratios were computed. The authors identified 9,044 cancer cases in a cohort of 325,228 licensees. Rate ratios for all sites combined suggested lower incidence among both cosmetologists (rate ratio = 0.84, 95% confidence interval (CI): 0.82, 0.86) and manicurists (rate ratio = 0.87, 95% CI: 0.84, 0.90). Proportional incidence ratios were modestly elevated for thyroid cancer among all licensees (proportional incidence ratio = 1.13, 95% CI: 1.04, 1.23) and for lung cancer among manicurists (proportional incidence ratio = 1.21, 95% CI: 1.07, 1.36). Although there did not appear to be a cancer excess, these findings may be artifactually influenced by limitations in demographic information available from the licensee files. Additionally, the relatively young ages of cohort members and demographic shifts in the industry composition in recent years suggest a need for further follow-up.

Control selection strategies in case-control studies of childhood diseases.

To address concerns regarding the representativeness of controls in case-control studies, two selection strategies were evaluated in a study of childhood leukemia, which commenced in California in 1995. The authors selected two controls per case: one from among children identified by using computerized birth records and located successfully, the other from a roster of friends; both were matched on demographic factors. Sixty-four birth certificate-friend control pairs were enrolled (n = 128). Additionally, 192 "ideal" controls were selected without tracing from the birth records. Data on parental ages, parental education, mother's reproductive history, and birth weight were obtained from the birth certificates of all 320 subjects. For all variables except birth weight, the differences between birth certificate and ideal controls were smaller than those between friend and ideal controls. None of the differences between birth certificate and ideal controls was significant, whereas two factors were significantly different between friend and ideal controls. These findings suggest that friend controls may be less representative than birth certificate controls. Despite difficulty in tracing and a seemingly low participation rate (49.0% for 560 enrolled birth certificate controls), using birth records to recruit controls appears to provide a representative sample of children and an opportunity to assess the representativeness of controls.

Cancer incidence in California flight attendants (United States).

OBJECTIVE: To examine unusual exposure opportunities to flight crews from chemicals, cosmic radiation, and electric and magnetic fields. METHODS: This project evaluated the incidence of cancers of the breast and other sites among Association of Flight Attendants (AFA) members residing in California. AFA membership files were matched to California's statewide cancer registry to identify a total of 129 newly diagnosed invasive cancers among AFA members with California residential histories between 1988 and 1995. RESULTS: Compared to the general population, female breast cancer incidence was over 30% higher than expected, and malignant melanoma incidence was roughly twice that expected. Both of these are cancers that are associated with higher socioeconomic status and have been suggestively associated with various sources of radiation. CONCLUSIONS: Consistent with the results from Nordic studies of cabin crews and a recent meta-analysis of prior studies, these data suggest that follow-up investigations should focus on the potential relative contribution of workplace exposures and lifestyle characteristics to the higher rates of disease for these two cancers.