Indoor coal use associated with possible impairment of early childhood growth

Children raised in homes using indoor coal for cooking or heating appear to be about a half-inch shorter at age 36 months than those in households using other fuel sources, according to a report posted online today that will appear in the June print issue of Archives of Pediatrics and Adolescent Medicine, one of the JAMA/Archives journals.

'Use of coal for indoor heating is widely prevalent in some countries, exposing millions of people to indoor air pollution from coal smoke,' the authors write as background information in the article. 'Coal combustion emits chemicals such as fluorine, selenium, mercury, arsenic, polycyclic aromatic hydrocarbons (PAHs), sulphur dioxide and nitrogen dioxide into the indoor air, and these chemicals may form residues on household surfaces and food. Often, exposures are prolonged owing to inadequate ventilation.'

Prenatal exposure to pollutants has been linked to restricted growth in utero, shorter length at birth, smaller head circumference and early-childhood cognitive deficits. To determine whether exposure to coal byproducts in the years following birth - a period marked by rapid development - also may adversely affect development, Rakesh Ghosh, Ph.D., of University of California, Davis, and colleagues tracked 1,133 children in the Czech Republic from birth to age 36 months. Data was gathered from questionnaires filled out by mothers and from medical records.

Among households in the study, 10.2 percent used coal for indoor heating or cooking and 6.8 percent used wood; 46.8 percent of wood users and 22.4 percent of coal users also used other fuel sources. At age 36 months, boys in coal-burning households were about 1.34 centimetres (0.52 inches) shorter than boys in households using other fuels, and girls raised in homes that used coal were about 1.3 centimetres (0.52 inches) shorter than girls in other homes.

There was no association between burning wood in the home and children's height, perhaps because households that used wood tended to use other fuels as well, the authors note.

Combined exposure to coal use and cigarette smoke was associated with even greater reductions in height; these children were about 2.09 centimetres (0.82 inches) shorter than children who were not exposed to pollutants from either source.

'These findings reaffirm that the negative impact of indoor air pollution from coal may extend beyond the respiratory system of children and indicate possible systemic effects,' the authors write. Exposure to coal smoke may impair growth through several mechanisms; for example, some compounds in the smoke have been identified as endocrine disruptors, which interfere with cell growth and differentiation.

'Because weight and length or height during infancy and childhood are considered to be predictors of morbidity such as obesity and mortality from malnutrition and infections, and in light of an estimated 50 percent of the world population using coal and solid biomass as a domestic fuel, knowledge of such an adverse impact on child health is vital from an international child health perspective,' the authors conclude.