Katherine J. Hoggatt

Estimated Deaths Attributable to Social Factors in the United States

OBJECTIVES We estimated the number of deaths attributable to social factors in the United States. METHODS We conducted a MEDLINE search for all English-language articles published between 1980 and 2007 with estimates of the relation between social factors and adult all-cause mortality. We calculated summary relative risk estimates of mortality, and we obtained and used prevalence estimates for each social factor to calculate the population-attributable fraction for each factor. We then calculated the number of deaths attributable to each social factor in the United States in 2000. RESULTS Approximately 245,000 deaths in the United States in 2000 were attributable to low education, 176,000 to racial segregation, 162,000 to low social support, 133,000 to individual-level poverty, 119,000 to income inequality, and 39,000 to area-level poverty. CONCLUSIONS The estimated number of deaths attributable to social factors in the United States is comparable to the number attributed to pathophysiological and behavioral causes. These findings argue for a broader public health conceptualization of the causes of mortality and an expansive policy approach that considers how social factors can be addressed to improve the health of populations.

Meeting Report: Atmospheric Pollution and Human Reproduction

Background There is a growing body of epidemiologic literature reporting associations between atmospheric pollutants and reproductive outcomes, particularly birth weight and gestational duration. Objectives The objectives of our international workshop were to discuss the current evidence, to identify the strengths and weaknesses of published epidemiologic studies, and to suggest future directions for research. Discussion Participants identified promising exposure assessment tools, including exposure models with fine spatial and temporal resolution that take into account time–activity patterns. More knowledge on factors correlated with exposure to air pollution, such as other environmental pollutants with similar temporal variations, and assessment of nutritional factors possibly influencing birth outcomes would help evaluate importance of residual confounding. Participants proposed a list of points to report in future publications on this topic to facilitate research syntheses. Nested case–control studies analyzed using two-phase statistical techniques and development of cohorts with extensive information on pregnancy behaviors and biological samples are promising study designs. Issues related to the identification of critical exposure windows and potential biological mechanisms through which air pollutants may lead to intrauterine growth restriction and premature birth were reviewed. Conclusions To make progress, this research field needs input from toxicology, exposure assessment, and clinical research, especially to aid in the identification and exposure assessment of feto-toxic agents in ambient air, in the development of early markers of adverse reproductive outcomes, and of relevant biological pathways. In particular, additional research using animal models would help better delineate the biological mechanisms underpinning the associations reported in human studies.

Methodological issues in studies of air pollution and reproductive health

In the past decade there have been an increasing number of scientific studies describing possible effects of air pollution on perinatal health. These papers have mostly focused on commonly monitored air pollutants, primarily ozone (O(3)), particulate matter (PM), sulfur dioxide (SO(2)), carbon monoxide (CO), and nitrogen dioxide (NO(2)), and various indices of perinatal health, including fetal growth, pregnancy duration, and infant mortality. While most published studies have found some marker of air pollution related to some types of perinatal outcomes, variability exists in the nature of the pollutants and outcomes associated. Synthesis of the findings has been difficult for various reasons, including differences in study design and analysis. A workshop was held in September 2007 to discuss methodological differences in the published studies as a basis for understanding differences in study findings and to identify priorities for future research, including novel approaches for existing data. Four broad topic areas were considered: confounding and effect modification, spatial and temporal exposure variations, vulnerable windows of exposure, and multiple pollutants. Here we present a synopsis of the methodological issues and challenges in each area and make recommendations for future study. Two key recommendations include: (1) parallel analyses of existing data sets using a standardized methodological approach to disentangle true differences in associations from methodological differences among studies; and (2) identification of animal studies to inform important mechanistic research gaps. This work is of critical public health importance because of widespread exposure and because perinatal outcomes are important markers of future child and adult health.

Estimated Effects of Disinfection By-Products on Preterm Birth in a Population Served by a Single Water Utility

Objectives We evaluated the association between drinking-water disinfection by-products and preterm births using improved exposure assessment and more appropriate analysis methods than used in prior studies. Methods During 1999–2001, vital record data were obtained for a large, racially diverse population residing in 27 Massachusetts communities that received drinking water from a single public utility. This water system was monitored weekly for total trihalomethanes (TTHM), and it maintained geographically stable total TTHM levels system-wide during the study period. We employed proportional hazards regression to examine the effects of trimester-specific and shorter-term peak exposures to TTHM in drinking water late in pregnancy on preterm births in 37,498 singletons. Results For all women, our data suggested no more than a small increase, if any, in risk for delivering a preterm baby when exposed to ≥ 60 μg/L TTHM during the 4 weeks before birth [hazard ratio (HR) = 1.13; 95% confidence interval (CI), 0.95–1.35]. However, women who depended on a governmental source of payment for prenatal care were at increased risk when exposed at such levels late in gestation (HR = 1.39; 95% CI, 1.06–1.81). In contrast, exposure to high levels of TTHM during the second trimester and high exposure throughout pregnancy resulted in a 15–18% reduction in risk for preterm delivery in our population. Conclusions This finding confirms previous reports of a negative association during the second trimester. Our data also suggested a possible positive association with shorter-term third-trimester TTHM exposure in mothers of lower socioeconomic status.

Air pollutant exposure and preterm and term small-for-gestational-age births in Detroit, Michigan: Long-term trends and associations

Studies in a number of countries have reported associations between exposure to ambient air pollutants and adverse birth outcomes, including low birth weight, preterm birth (PTB) and, less commonly, small for gestational age (SGA). Despite their growing number, the available studies have significant limitations, e.g., incomplete control of temporal trends in exposure, modest sample sizes, and a lack of information regarding individual risk factors such as smoking. No study has yet examined large numbers of susceptible individuals. We investigated the association between ambient air pollutant concentrations and term SGA and PTB outcomes among 164,905 singleton births in Detroit, Michigan occurring between 1990 and 2001. SO(2), CO, NO(2), O(3) and PM(10) exposures were used in single and multiple pollutant logistic regression models to estimate odds ratios (OR) for these outcomes, adjusted for the infants sex and gestational age, the mothers race, age group, education level, smoking status and prenatal care, birth season, site of residence, and long-term exposure trends. Term SGA was associated with CO levels exceeding 0.75ppm (OR=1.14, 95% confidence interval=1.02-1.27) and NO(2) exceeding 6.8ppb (1.11, 1.03-1.21) exposures in the first month, and with PM(10) exceeding 35μg/m(3) (1.22, 1.03-1.46) and O(3) (1.11, 1.02-1.20) exposure in the third trimester. PTB was associated with SO(2) (1.07, 1.01-1.14) exposure in the last month, and with (hourly) O(3) exceeding 92ppb (1.08, 1.02-1.14) exposure in the first month. Exposure to several air pollutants at modest concentrations was associated with adverse birth outcomes. This study, which included a large Black population, suggests the importance of the early period of pregnancy for associations between term SGA with CO and NO(2), and between O(3) with PTB; and the late pregnancy period for associations between term SGA and O(3) and PM(10), and between SO(2) with PTB. It also highlights the importance of accounting for individual risk factors such as maternal smoking, maternal race, and long-term trends in air pollutant levels and adverse birth outcomes in evaluating relationships between pollutant exposures and adverse birth outcomes.

Alcohol and Drug Misuse, Abuse, and Dependence in Women Veterans

We conducted a systematic literature review on substance misuse, abuse, and dependence in women veterans, including National Guard/reserve members. We identified 837 articles published between 1980 and 2013. Of 56 included studies, 32 reported rates of alcohol misuse, binge drinking, or other unhealthy alcohol use not meeting diagnostic criteria for abuse or dependence, and 33 reported rates of drug misuse or diagnosed alcohol or drug use disorders. Rates ranged from 4% to 37% for alcohol misuse and from 7% to 25% for binge drinking; among Veterans Health Administration (VA) health-care system outpatients, rates ranged from 3% to 16% for substance use disorder. Studies comparing women veterans and civilians reported no clear differences in binge or heavy drinking. Substance misuse rates were generally lower among women veterans than men veterans. Substance misuse was associated with higher rates of trauma, psychiatric and medical conditions, and increased mortality and suicide rates. Most studies included only VA patients, and many used only VA medical record data; therefore, the reported substance misuse rates likely do not reflect true prevalence. Rates also varied by assessment method, source of data, and the subgroups studied. Further efforts to develop epidemiologically valid prevalence estimates are needed to capture the true health burden of substance misuse in women veterans, particularly those not using VA care.

Substance Use Among Women Veterans: Epidemiology to Evidence-Based Treatment

An increasing percentage of women are U.S. Military Veterans. We review the substance misuse rates and comorbidities and the risk factors for and consequences of substance use among women Veterans. Women Veterans may have higher rates of substance misuse and comorbid psychiatric and medical disorders than male Veterans and women who are not Veterans. Studies support the AUDIT-C as a scaled marker of alcohol-related risk among female Veterans, but validated drug screening instruments are needed. We discuss evidence-based approaches in terms of treating women Veterans’ substance misuse in primary and specialty care settings, along with knowledge gaps and potential research priorities to improve care in this special population.

Exploratory data mining analysis identifying subgroups of patients with depression who are at high risk for suicide

OBJECTIVE Although prior research has identified a number of separate risk factors for suicide among patients with depression, little is known about how these factors may interact to modify suicide risk. Using an empirically based decision tree analysis for a large national sample of Veterans Affairs (VA) health system patients treated for depression, we identified subgroups with particularly high or low rates of suicide. METHOD We identified 887,859 VA patients treated for depression between April 1, 1999, and September 30, 2004. Randomly splitting the data into 2 samples (primary and replication samples), we developed a decision tree for the primary sample using recursive partitioning. We then tested whether the groups developed within the primary sample were associated with increased suicide risk in the replication sample. RESULTS The exploratory data analysis produced a decision tree with subgroups of patients at differing levels of risk for suicide. These were identified by a combination of factors including a co-occurring substance use disorder diagnosis, male sex, African American race, and psychiatric hospitalization in the past year. The groups developed as part of the decision tree accurately discriminated between those with and without suicide in the replication sample. The patients at highest risk for suicide were those with a substance use disorder who were non-African American and had an inpatient psychiatric stay within the past 12 months. CONCLUSIONS Study findings suggest that the identification of depressed patients at increased risk for suicide is improved through the examination of higher order interactions between potential risk factors.

National Prevalence and Correlates of Alcohol Misuse in Women Veterans

Our goal was to estimate the prevalence and correlates of alcohol misuse in women veterans and to assess the associations between alcohol misuse and mental health (MH) care utilization in a group comprising both Veterans Health Administration (VA) healthcare system users and non-users. We assessed alcohol misuse using survey-based AUDIT-C scores. The prevalence of alcohol misuse was 27% in VA users and 32% in non-users. Prevalence rates were higher for VA users who were younger, served in OEF/OIF, or had combat exposure and for VA non-users who screened positive for posttraumatic stress disorder or sexual assault in the military. In contrast to VA users, VA non-users with alcohol misuse had a low prevalence of past-year MH care despite having indications of MH care need. Our results on alcohol misuse prevalence, its correlates, and its association with MH care may aid program planning and resource allocation in VA and non-VA settings.

Antidepressant Agents and Suicide Death Among US Department of Veterans Affairs Patients in Depression Treatment

Background Studies report mixed findings regarding antidepressant agents and suicide risks, and few examine suicide deaths. Studies using observational data can accrue the large sample sizes needed to examine suicide death, but selection biases must be addressed. We assessed associations between suicide death and treatment with the 7 most commonly used antidepressants in a national sample of Department of Veterans Affairs patients in depression treatment. Multiple analytic strategies were used to address potential selection biases. Methods We identified Department of Veterans Affairs patients with depression diagnoses and new antidepressant starts between April 1, 1999, and September 30, 2004 (N = 502,179). Conventional Cox regression models, Cox models with inverse probability of treatment weighting, propensity-stratified Cox models, marginal structural models (MSM), and instrumental variable analyses were used to examine relationships between suicide and exposure to bupropion, citalopram, fluoxetine, mirtazapine, paroxetine, sertraline, and venlafaxine. Results Crude suicide rates varied from 88 to 247 per 100,000 person-years across antidepressant agents. In multiple Cox models and MSMs, sertraline and fluoxetine had lower risks for suicide death than paroxetine. Bupropion had lower risks than several antidepressants in Cox models but not MSMs. Instrumental variable analyses did not find significant differences across antidepressants. Discussion Most antidepressants did not differ in their risk for suicide death. However, across several analytic approaches, although not instrumental variable analyses, fluoxetine and sertraline had lower risks of suicide death than paroxetine. These findings are congruent with the Food and Drug Administration meta-analysis of randomized controlled trials reporting lower risks for “suicidality” for sertraline and a trend toward lower risks with fluoxetine than for other antidepressants. Nevertheless, divergence in findings by analytic approach suggests caution when interpreting results.