Predictors of PFOA Levels in a Community Surrounding a Chemical Plant

BACKGROUND. Perfluorooctanoic acid (PFOA) is considered a probable human carcinogen by the U.S. Environmental Protection Agency. It does not exist in nature but has been used widely since World War II. It is present in the serum of most Americans at about 4-5 ng/mL, although the routes of exposure remain unknown. OBJECTIVES. We examined predictors of PFOA in mid-Ohio Valley residents living near a chemical plant that until recently released large quantities of PFOA into the environment, contaminating drinking water. METHODS. We studied 69,030 residents in six contaminated water districts who participated in a 2005-2006 survey involving a questionnaire and blood tests. Of these, 64,251 had complete data on PFOA and covariates. We also analyzed a subset (71%) for whom we had occupational history. We ran linear regression models to determine serum PFOA predictors. RESULTS. Mean PFOA serum level was 83.0 ng/mL (median, 28.2). The most important predictors were current (median for all districts, 38.4; highest district, 224.1) and past (median, 18.6) residence in contaminated water districts, and current (median, 147.8) and past (median, 74.9) employment at the chemical plant (R^2 model = 0.55). PFOA was higher for males, those consuming local vegetables, and those using well water rather than public water, and lower for those using bottled water. PFOA was higher at younger and older ages. CONCLUSIONS. PFOA levels in this population varied with distance of residence from the plant and employment at the plant. Effects of age and sex reflected prior findings. Effects of other demographic and lifestyle covariates were relatively weak

Design, Methods, and Population for a Study of PFOA Health Effects among Highly Exposed Mid-Ohio Valley Community Residents and Workers

Background: A cohort of community residents and workers is the basis for a series of epidemiologic studies of a Mid-Ohio Valley population with substantial perfluorooctanoic acid (PFOA) exposure due to releases from a chemical plant. Objectives: We describe study design, methods, and study participants for a longitudinal cohort study of associations between PFOA exposure and adult chronic diseases. Methods: Two cohorts were formed, one recruited from community residents who participated in a previous community-wide survey, and one from plant workers. Study participants were interviewed during 2008–2011 regarding demographics, health-related behaviors, and personal history of chronic diseases. Reported diseases were validated through medical records review and registry matching. Here we describe cohort characteristics, compare survey respondents and nonrespondents, provide data on the number of diseases reported and validated, and describe historical estimates of serum PFOA concentrations over time. Results: The final combined cohort included 32,254 participants (28,541 community; 3,713 worker). Participation rates were high (community, 81.5%; worker, 72.9% of target population). The final population from each cohort was representative of the target population in terms of demographic characteristics and measured serum PFOA concentrations in 2005–2006. The study had a wide exposure range and the number of reported cases of chronic diseases was high, resulting in greater power to detect associations than has been the case for many previous studies. Conclusions: This is the largest study to date of the health effects of PFOA. The information from this cohort is being used to examine associations between PFOA exposure and multiple adult chronic diseases

Indirect estimation of the prevalence of spinal muscular atrophy Type I, II, and III in the United States

Abstract Background Spinal muscular atrophy (SMA) is a progressive, devastating disease and a leading inherited cause of infant mortality. The limited population-based literature is confined to small regional studies. Estimates of prevalence are needed to characterize the burden of SMA and to understand trends in prevalence by disease type as new treatments become available. The reported estimates of SMA genotype prevalence at birth consistently range from 8.5–10.3 per 100,000 live births, with a mid-range estimate of 9.4 per 100,000. Among infants born with an SMA genotype, it is reported that ~58% will develop SMA Type I, 29% will develop Type II, and 13% will develop Type III, respectively. Results Using evidence from peer-reviewed literature for SMA birth prevalence, age at symptom onset, and SMA type-specific survival, and incorporating United States vital statistics, we constructed life tables to estimate prevalence for SMA Types I, II, and III in the United States. We estimated the number of prevalent cases in the US to be 8526, 9429, and 10,333 based on a birth prevalence of 8.5, 9.4, and 10.3, respectively (the lower, midpoint, and upper ends of the reported range). Assuming the midpoint of 9.4 and US-reported survival, the type-specific population prevalence estimates were 1610 for SMA Type I, 3944 for SMA Type II, and 3875 for SMA Type III. Evidence-based estimates of the number of people living with SMA in the United States in the published literature were previously unavailable. Conclusions In the absence of a survey or other means to directly estimate prevalence in the US population, estimates can be calculated indirectly using a life table

Additional file 4: Table S4. of Indirect estimation of the prevalence of spinal muscular atrophy Type I, II, and III in the United States

Methods. Table showing methods. (DOCX 16 kb

Additional file 1: Table S1. of Indirect estimation of the prevalence of spinal muscular atrophy Type I, II, and III in the United States

Summary of contemporary published estimates of SMA birth prevalence. Table showing summary of contemporary published estimates of SMA birth prevalence. (DOCX 23 kb

Additional file 2: Table S2. of Indirect estimation of the prevalence of spinal muscular atrophy Type I, II, and III in the United States

Summary of survival probabilities for patients with SMA Type I in the United States. Table showing summary of survival probabilities for patients with SMA Type I in the United States. (DOCX 20 kb

Additional file 3: Table S3. of Indirect estimation of the prevalence of spinal muscular atrophy Type I, II, and III in the United States

Summary of survival probabilities for patients with SMA Type II in the United States. Table showing summary of survival probabilities for patients with SMA Type II in the United States. (DOCX 14 kb