Early exposure to arsenic can lead to lingering respiratory effects among males

Exposure to arsenic in utero and during early childhood has long been linked to various respiratory illnesses that could have lifelong effects. Continued exposure to the toxin has been associated with chronic cough, dyspnea and breathlessness.

Growing evidence shows that early-life exposure to arsenic leads to continued health effects later in life, but a recent study has shown that long-term effects tend to be more prevalent in males than they are in females. It found that by the age range of 14 to 26, there was little remaining evidence of chronic respiratory effects in females, but pronounced effects persisted in males.

“This is the first longitudinal cohort study of respiratory effects in adolescents and young adults who were exposed to arsenic in utero and in early childhood,” said Taehyun Roh, PhD, one of the study’s authors and assistant professor in the Department of Epidemiology and Biostatistics at the Texas A&M School of Public Health.

The study was recently published in Environmental Epidemiology, an official journal of the International Society for Environmental Epidemiology.

The current study is a follow up to a previous study conducted by the same group of researchers that examined the chronic respiratory effects of arsenic in early childhood (ages 7 to 17) in individuals in Matlab, Bangladesh.

In the initial study, one group of children had been exposed to high concentrations of inorganic arsenic, which is highly toxic, through drinking water in utero and during early childhood, and a second group had no known exposure to the toxin. The exposed children, both females and males, showed an increase in respiratory symptoms.

“Our study provides extensive evidence that there are long-term effects resulting from early life exposure to arsenic,” Roh said. “So every effort should be made to reduce exposure, especially in early life.”

Although studies have been conducted on the effects of arsenic exposure in early childhood, the researchers noted that so far, to their knowledge, there have been no studies that have followed children with well-documented early-life exposure to assess the long-term health consequences in adolescents and young adults.

In the most recent study, 463 individuals in the 14 to 26 age range agreed to participate. Individuals were interviewed regarding respiratory symptoms and lung function was measured. Additionally, data was collected on smoking habits, body mass index and number of rooms in the individual’s home as a measure of socioeconomic status.

Among the participants, 135 were exposed to high arsenic concentrations early in life, 100 were exposed to medium arsenic concentrations and 228 were exposed to low arsenic concentrations. Males represented 49.5 percent of the individuals, and females made up 50.5 percent of the respondents.

What the researchers found was that the respiratory effects from early childhood exposure were still present in males, while the females who had been exposed in early childhood did not show the respiratory effects.

According to the researchers, males were more likely to report various respiratory symptoms including dry cough, as well as being awoken due to shortness of breath and asthma. The effects from the exposure, however, were not evident in females.

The researchers also observed reduced lung function among the male participants which were not present when they were younger.

“Although these sex specific findings are somewhat surprising, many studies have reported gender differences in arsenic effects,” Roh said “Differences in arsenic effects between males and females may be due to sex differences in arsenic metabolism. Further research may help elucidate these puzzling observations.”

Roh’s co-authors on the study include, Md Alfazal Khan, Syed Imran Ahmed and S.M. Tafsir Hasan, Nutrition and Clinical Services Division, International Centre for Diarrhoeal Disease Research, Bangladesh; Meera Hira-Smith, Jane Liaw, John Balmes, Yan Yuan, Craig Steinmaus and Allan H. Smith, Arsenic Health Effects Research Program, School of Public Health, University of California, Berkley; Mohammad Yunus, Maternal and Child Health Division, International Centre for Diarrhoeal Disease Research, Bangladesh; Rubhana Raqib, Infectious Disease Division, International Centre for Diarrhoeal Disease Research, Bangladesh; David Kalman, Department of Environmental and Occupational Health Sciences, School of Public Health, University of Washington.