Academic journal article Environmental Health Perspectives

Occupational Lead Exposure and Associations with Selected Cancers: The Shanghai Men's and Women's Health Study Cohorts

Academic journal article Environmental Health Perspectives

Occupational Lead Exposure and Associations with Selected Cancers: The Shanghai Men's and Women's Health Study Cohorts

Article excerpt

Introduction

Lead is a metal that is commonly used in many industrial settings worldwide, and it is an important environmental pollutant. The occurrence of lead in the environment has decreased greatly in recent decades because of the elimination of most leaded gasoline; however, occupational exposures continue primarily via lead in the storage battery industry and lead pigments in paints [International Agency for Research on Cancer (IARC) 2006]. Occupations that have had frequent high exposures include battery-production workers, battery-recycling workers, foundry workers, lead chemical workers, lead smelter and refinery workers, leaded-glass workers, pigment workers, construction workers, and radiator-repair workers. In most developed countries, strict controls have reduced environmental and occupational exposures to lead; however, lead exposure continues to be an issue in developing countries with rapid industrialization, such as China (Gottesfeld and Pokhrel 2011; IARC 2006). Lead as a gasoline additive is a large contributor to environmental lead exposure, and developing countries, such as China, have generally lagged behind developed countries in banning lead in gasoline. Leaded gasoline was eventually banned in 1999 in China and was gradually phased out over the 2000s; however, other environmental sources continue to contribute to lead exposure in China. The occupational exposure limit (OEL) for lead and inorganic compounds of lead was set in China in 1979 and was based on maximum allowable concentrations of 0.05 mg/[m.sup.3] for lead dust and 0.03 mg/[m.sup.3] for lead fume (Liang et al. 1995). The OELs remained at the same levels but were based on time-weighted averages from 2002 onward, similar to the exposure standards for lead in the United States.

High lead exposure is known to be harmful, particularly for children; established health effects include damage to the brain and nervous system, gastrointestinal problems, anemia, liver and kidney damage, fertility problems, and developmental delays (Abadin et al. 2007). Lead is also a suspected carcinogen, with inorganic lead compounds currently designated by the IARC as probably carcinogenic (Group 2A) based on limited evidence in humans and sufficient evidence in animals (IARC 2006). Organic lead compounds were designated by the IARC as not classifiable with regard to carcinogenicity (Group 3) owing to inadequate evidence. Epidemiologic evidence for carcinogenicity in workers exposed to inorganic lead suggests associations with cancers of the stomach, lung, kidney, brain, and meninges, although the totality of the evidence is inconsistent (IARC 2006; Rousseau et al. 2007; Steenland and Boffetta 2000). Very few previous studies have evaluated occupational lead exposure among women, although differences between the sexes have been observed for lead exposure and metabolism (Vahter et al. 2007). There is thus a need for additional well-designed epidemiologic studies including both men and women to resolve the question of whether lead is a carcinogen (Ward et al. 2010). To that end, we investigated the association between occupational lead exposure and risk of cancers of the stomach, lung, kidney, brain, and meninges in two large prospective cohort studies of women and men in Shanghai, China.

Methods

Study population. The Shanghai Women's Health Study (SWHS) and the Shanghai Men's Health Study (SMHS) are two population-based prospective cohort studies based in Shanghai, China. The rationale, design, and methods of both studies have been described in detail previously (Shu et al. 2015; Zheng et al. 2005). Briefly, using a roster provided by the community office, 81,170 permanent female residents 40-70 years of age were approached for the SWHS study between 1996 and 2000 (Zheng et al. 2005), and 83,033 permanent male residents 40-74 years of age were approached for the SMHS between 2002 and 2006 (Shu et al. 2015). Of the 81,170 eligible women, 75,221 participated in the SWHS study, for an overall response rate of 92. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.