Steve Wing

A conceptual model of work and health disparities in the United States.

Recent research in medicine and public health highlights differences in health related to race, ethnicity, socioeconomic status, and gender. These inequalities, often labeled “disparities,” are pervasive and pertain to the major causes of morbidity, mortality, and lost life years. Often ignored in discussions of health disparities is the complex role of work, including not only occupational exposures and working conditions, but also benefits associated with work, effects of work on families and communities, and policies that determine where and how people work. The authors argue that work should be considered explicitly as a determinant of health disparities. Their conceptual model and empirical evidence, built on previous contributions, describe how work contributes to disparities in health on multiple levels. The examples focus on the United States, but many of the key conceptual features can also be applied to other countries. The model emphasizes behaviors and characteristics of institutions rather than individual workers. This approach avoids a focus on individual responsibility alone, which may lead to victim blaming and failure to emphasize policies and institutional factors that affect large populations and systematically create and maintain racial, gender, and socioeconomic disparities in health.

Ionizing Radiation and Chronic Lymphocytic Leukemia

The U.S. government recently implemented rules for awarding compensation to individuals with cancer who were exposed to ionizing radiation while working in the nuclear weapons complex. Under these rules, chronic lymphocytic leukemia (CLL) is considered to be a nonradiogenic form of cancer. In other words, workers who develop CLL automatically have their compensation claim rejected because the compensation rules hold that the risk of radiation-induced CLL is zero. In this article we review molecular, clinical, and epidemiologic evidence regarding the radiogenicity of CLL. We note that current understanding of radiation-induced tumorigenesis and the etiology of lymphatic neoplasia provides a strong mechanistic basis for expecting that ionizing radiation exposure increases CLL risk. The clinical characteristics of CLL, including prolonged latency and morbidity periods and a low case fatality rate, make it relatively difficult to evaluate associations between ionizing radiation and CLL risk via epidemiologic methods. The epidemiologic evidence of association between external exposure to ionizing radiation and CLL is weak. However, epidemiologic findings are consistent with a hypothesis of elevated CLL mortality risk after a latency and morbidity period that spans several decades. Our findings in this review suggest that there is not a persuasive basis for the conclusion that CLL is a nonradiogenic form of cancer.

Contact with beach sand among beachgoers and risk of illness.

Recent studies of beach sand fecal contamination have triggered interest among scientists and in the media. Although evidence shows that beach sand can harbor high concentrations of fecal indicator organisms, as well as fecal pathogens, illness risk associated with beach sand contact is not well understood. Beach visitors at 7 US beaches were enrolled in the National Epidemiological and Environmental Assessment of Recreational Water (NEEAR) Study during 2003-2005 and 2007 and asked about sand contact on the day of their visit to the beach (digging in the sand, body buried in the sand). Then, 10-12 days after their visit, participants were telephoned to answer questions about any health symptoms experienced since the visit. The authors completed 27,365 interviews. Digging in the sand was positively associated with gastrointestinal illness (adjusted incidence proportion ratio (aIPR) = 1.13, 95% confidence interval (CI): 1.02, 1.25) and diarrhea (aIPR = 1.20, 95% CI: 1.05, 1.36). The association was stronger between those buried in the sand and gastrointestinal illness (aIPR = 1.23, 95% CI: 1.05, 1.43) and diarrhea (aIPR = 1.24, 95% CI: 1.01, 1.52). Nonenteric illnesses did not show a consistent association with sand contact activities. Sand contact activities were associated with enteric illness at beach sites. Variation in beach-specific results suggests that site-specific factors may be important in the risk of illness following sand exposure.

The Shifting Stroke Belt Changes in the Geographic Pattern of Stroke Mortality in the United States, 1962 to 1988

BACKGROUND AND PURPOSE The factors that contribute to the Stroke Belt--a concentration of high stroke mortality rates in the southeastern United States--remain unidentified. Previous hypotheses that focused on physical properties of the area have not been confirmed. This study describes changes in the locations of areas with the highest rates of stroke mortality and the implications for new hypotheses regarding the Stroke Belt. METHODS We calculated annual, age-adjusted stroke mortality rates for black women, black men, white women, and white men for the years 1962 to 1988 using a three-piece log-linear regression model. Maps were produced with the state economic area (SEA) as the unit of analysis. The baseline Stroke Belt was defined as the area with the largest concentration of high-quintile SEAs in 1962. RESULTS The concentration of high-rate SEAs tended to shift away from the Piedmont region of the Southeast and toward the Mississippi River valley. For example, whereas among black women in 1962, 72% of SEAs in the baseline Stroke Belt were in the highest quintile, by 1988 this percentage had dropped to 48%. Similar patterns were observed for the other race/sex groups. CONCLUSIONS Temporal changes in the location of areas with the highest stroke mortality rates suggest that new hypotheses for understanding the geographic pattern of stroke mortality should consider temporal trends in a variety of medical, socioeconomic, and behavioral factors.

Air Pollution and Odor in Communities Near Industrial Swine Operations

Background Odors can affect health and quality of life. Industrialized animal agriculture creates odorant compounds that are components of a mixture of agents that could trigger symptoms reported by neighbors of livestock operations. Objective We quantified swine odor episodes reported by neighbors and the relationships of these episodes with environmental measurements. Methods Between September 2003 and September 2005, 101 nonsmoking volunteers living within 1.5 mi of industrial swine operations in 16 neighborhoods in eastern North Carolina completed twice-daily odor diaries for approximately 2 weeks. Meteorological conditions, hydrogen sulfide, and particulate matter ≤ 10 μm in aerodynamic diameter (PM10) were monitored in each neighborhood. We used mixed models to partition odor variance within and between people and between neighborhoods, and to quantify relationships between environmental factors and odor. Results Participants reported 1,655 episodes of swine odor. In nine neighborhoods, odor was reported on more than half of study-days. Odor ratings were related to temperature, PM10, and semivolatile PM10 in standard but not mixed models. In mixed models, odor increased 0.15 ± 0.05 units (mean ± SE) for a 1-ppb increase in H2S, and 0.45 ± 0.14 units for a 10-μg/m3 increase in PM10 at wind speeds > 6.75 miles per hour. The odds of reporting a change in daily activities due to odor increased 62% for each unit increase in average odor during the prior 12 hr (t-value = 7.17). Conclusions This study indicates that malodor from swine operations is commonly present in these communities and that the odors reported by neighbors are related to objective environmental measurements and interruption of activities of daily life.

Air Pollution, Lung Function, and Physical Symptoms in Communities Near Concentrated Swine Feeding Operations

Background: Concentrated animal feeding operations emit air pollutants that may affect health. We examined associations of reported hog odor and of monitored air pollutants with physical symptoms and lung function in people living within 1.5 miles of hog operations. Methods: Between September 2003 and September 2005, we measured hydrogen sulfide (H2S), endotoxin, and particulate matter (PM10, PM2.5, and PM2.5–10) for approximately 2-week periods in each of 16 eastern North Carolina communities. During the same time periods, 101 adults sat outside their homes twice a day for 10 minutes, reported hog odor and physical symptoms, and measured their lung function. Conditional fixed-effects logistic and linear regression models were used to derive estimates of associations. Results: The log odds (±1 standard error) of acute eye irritation following 10 minutes outdoors increased by 0.53 (±0.06) for every unit increase in odor, by 0.15 (±0.06) per 1 ppb of H2S, and by 0.36 (±0.11) per 10 &mgr;g/m3 of PM10. Odor and H2S were also associated with irritation and respiratory symptoms in the previous 12 hours. The log odds of difficulty breathing increased by 0.50 (±0.15) per unit of odor. A 10 &mgr;g/m3 increase in mean 12-hour PM2.5 was associated with increased log odds of wheezing (0.84 ± 0.29) and declines in forced expiratory volume in 1 second (−0.04 ± 0.02 L). A 10 EU/mg increase in endotoxin was associated with increased log odds of sore throat (0.10 ± 0.05), chest tightness (0.09 ± 0.04), and nausea (0.10 ± 0.05). Conclusions: Pollutants measured near hog operations are related to acute physical symptoms in a longitudinal study using analyses that preclude confounding by time-invariant characteristics of individuals.

Asthma symptoms among adolescents who attend public schools that are located near confined swine feeding operations.

OBJECTIVES. Little is known about the health effects of living in close proximity to industrial swine operations. We assessed the relationship between estimated exposure to airborne effluent from confined swine feeding operations and asthma symptoms among adolescents who were aged 12 to 14 years. METHODS. During the 1999–2000 school year, 58169 adolescents in North Carolina answered questions about their respiratory symptoms, allergies, medications, socioeconomic status, and household environments. To estimate the extent to which these students may have been exposed during the school day to air pollution from confined swine feeding operations, we used publicly available data about schools (n = 265) and swine operations (n = 2343) to generate estimates of exposure for each public school. Prevalence ratios and 95% confidence intervals for wheezing within the past year were estimated using random-intercepts binary regression models, adjusting for potential confounders, including age, race, socioeconomic status, smoking, school exposures, and household exposures. RESULTS. The prevalence of wheezing during the past year was slightly higher at schools that were estimated to be exposed to airborne effluent from confined swine feeding operations. For students who reported allergies, the prevalence of wheezing within the past year was 5% higher at schools that were located within 3 miles of an operation relative to those beyond 3 miles and 24% higher at schools in which livestock odor was noticeable indoors twice per month or more relative to those with no odor. CONCLUSIONS. Estimated exposure to airborne pollution from confined swine feeding operations is associated with adolescents’ wheezing symptoms.

Livestock-Associated Methicillin and Multidrug Resistant Staphylococcus aureus Is Present among Industrial, Not Antibiotic-Free Livestock Operation Workers in North Carolina

Objectives Administration of antibiotics to food animals may select for drug-resistant pathogens of clinical significance, such as methicillin-resistant Staphylococcus aureus (MRSA). In the United States, studies have examined prevalence of MRSA carriage among individuals exposed to livestock, but prevalence of multidrug-resistant S. aureus (MDRSA) carriage and the association with livestock raised with versus without antibiotic selective pressure remains unclear. We aimed to examine prevalence, antibiotic susceptibility, and molecular characteristics of S. aureus among industrial livestock operation (ILO) and antibiotic-free livestock operation (AFLO) workers and household members in North Carolina. Methods Participants in this cross-sectional study were interviewed and provided a nasal swab for S. aureus analysis. Resulting S. aureus isolates were assessed for antibiotic susceptibility, multi-locus sequence type, and absence of the scn gene (a marker of livestock association). Results Among 99 ILO and 105 AFLO participants, S. aureus nasal carriage prevalence was 41% and 40%, respectively. Among ILO and AFLO S. aureus carriers, MRSA was detected in 7% (3/41) and 7% (3/42), respectively. Thirty seven percent of 41 ILO versus 19% of 42 AFLO S. aureus-positive participants carried MDRSA. S. aureus clonal complex (CC) 398 was observed only among workers and predominated among ILO (13/34) compared with AFLO (1/35) S. aureus-positive workers. Only ILO workers carried scn-negative MRSA CC398 (2/34) and scn-negative MDRSA CC398 (6/34), and all of these isolates were tetracycline resistant. Conclusions Despite similar S. aureus and MRSA prevalence among ILO and AFLO-exposed individuals, livestock-associated MRSA and MDRSA (tetracycline-resistant, CC398, scn-negative) were only present among ILO-exposed individuals. These findings support growing concern about antibiotics use and confinement in livestock production, raising questions about the potential for occupational exposure to an opportunistic and drug-resistant pathogen, which in other settings including hospitals and the community is of broad public health importance.

Fecal indicators in sand, sand contact, and risk of enteric illness among beachgoers

Background: Beach sand can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with sand contact remains unclear. Methods: In 2007, visitors at 2 recreational marine beaches were asked on the day of their visit about sand contact. Ten to 12 days later, participants answered questions about health symptoms since the visit. F+ coliphage, Enterococcus, Bacteroidales, fecal Bacteroides, and Clostridium spp. in wet sand were measured using culture and molecular methods. Results: We analyzed 144 wet sand samples and completed 4999 interviews. Adjusted odds ratios (aORs) were computed, comparing those in the highest tertile of fecal indicator exposure with those who reported no sand contact. Among those digging in sand compared with those not digging in sand, a molecular measure of Enterococcus spp. (calibrator cell equivalents/g) in sand was positively associated with gastrointestinal (GI) illness (aOR = 2.0 [95% confidence interval (CI) = 1.2–3.2]) and diarrhea (2.4 [1.4–4.2]). Among those buried in sand, point estimates were greater for GI illness (3.3 [1.3–7.9]) and diarrhea (4.9 [1.8–13]). Positive associations were also observed for culture-based Enterococcus (colony-forming units/g) with GI illness (aOR digging = 1.7 [1.1–2.7]) and diarrhea (2.1 [1.3–3.4]). Associations were not found among nonswimmers with sand exposure. Conclusions: We observed a positive relationship between sand-contact activities and enteric illness as a function of concentrations of fecal microbial pollution in beach sand.

Changing association between community occupational structure and ischaemic heart disease mortality in the United States.

The changing association between community occupational structure and ischaemic heart disease mortality in white men and women of the United States from 1968 to 1982 has been investigated. Occupational structure was represented by the proportion of workers in white-collar jobs. A negative association, with lower mortality in communities with higher levels of white-collar employment, emerged over the period in both men and women. The results for men may be interpreted as suggesting a recapitulation in the US of the changing association between social class and heart disease observed in Britain. Occupational structure, however, reflects resources and opportunities in a community derived from its contribution to the national and international economy. Thus the growing inequalities in heart disease mortality presented in this ecological study relate more appropriately to communities than to individual workers.