Indoor Wood-Burning Stove and Fireplace Use and Breast Cancer in a Prospective Cohort Study.

BACKGROUND: Indoor burning of fuel for heating or cooking releases carcinogens. Little is known about the impact of indoor air pollution from wood-burning stoves or fireplaces on breast cancer risk. OBJECTIVES: In a large prospective cohort study, we evaluated the risk of breast cancer in relation to indoor heating and cooking practices. METHODS: Sister Study participants (n=50,884) were recruited from 2003­2009. Breast cancer­free women in the United States or Puerto Rico, 35­74 y old, with a sister with breast cancer were eligible. Participants completed questionnaires on indoor heating and cooking practices for both their enrollment and their longest adult residence. Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between indoor heating/cooking and breast cancer. RESULTS: A total of 2,416 breast cancer cases were diagnosed during follow-up (mean=6.4 y). Having an indoor wood-burning stove/fireplace in the longest adult residence was associated with a higher breast cancer risk [HR=1.11 (95% CI: 1.01, 1.22)]; the risk increased with average frequency of use [≥once/week, HR=1.17 (95% CI: 1.02, 1.34)] (p for trend=0.01). An elevated HR was seen for women burning wood [HR=1.09 (95% CI: 0.98, 1.21)] or natural gas/propane [HR=1.15 (95% CI: 1.00, 1.32)]. No association was observed for burning artificial fire-logs [HR=0.98 (95% CI: 0.85, 1.12)] except among women from western states [HR=1.36 (95% CI: 1.02, 1.81)]. CONCLUSIONS: In this prospective study, using an indoor wood-burning stove/fireplace in the longest adult residence at least once a week and burning either wood or natural gas/propane was associated with a modestly higher risk of breast cancer. https://doi.org/10.1289/EHP827.

Antimüllerian hormone in relation to tobacco and marijuana use and sources of indoor heating/cooking.

OBJECTIVE: To evaluate exposure to tobacco, marijuana, and indoor heating/cooking sources in relation to antimüllerian hormone (AMH) levels. DESIGN: Cross-sectional analysis in a sample of premenopausal women (n = 913) enrolled in the Sister Study cohort (n = 50,884). SETTING: Not applicable. PATIENT(S): Women, ages 35-54 years at time of enrollment, with an archived serum sample and at least one intact ovary and classified as premenopausal. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Serum AMH (ng/mL) levels ascertained by ultrasensitive ELISA assay. RESULT(S): Lower AMH levels were associated with sources of indoor heating, including burning wood (-36.0%; 95% confidence interval [CI], -55.7%, -7.8%) or artificial fire logs (-45.8%; 95% CI, -67.2%, -10.4%) at least 10 times/year in a residential indoor stove/fireplace. Lower AMH levels were also observed in women who were current smokers of ≥20 cigarettes/day relative to nonsmokers (-56.2%; 95% CI, -80.3%, -2.8%) and in women with 10+ years of adult environmental tobacco smoke (ETS) exposure (-31.3%; 95% CI, -51.3%, -3.1%), but no associations were observed for marijuana use. CONCLUSION(S): We confirmed previously reported findings of lower AMH levels in current heavy smokers and also found associations for long-term ETS exposure and indoor burning of wood or artificial fire logs. These findings suggest that combustion by-products from common exposures can have toxic effects on the human ovary.

What are the main environmental exposures associated with elevated IgE in Cuban infants? A population-based study.

OBJECTIVE: Immunoglobulin E (IgE) plays a key role in allergy disease pathogenesis, but little is known about the environmental factors associated with higher IgE levels in infants. The aim of this study was to determine the risk factors for elevated serum total IgE infants living in Havana. METHODS: Eight hundred and seventy-seven infants provided blood samples. Data on allergic disease symptoms and a wide range of exposures were collected. RESULTS: The median IgE was 35 IU/ml (interquartile range 13-96). The risk of having an IgE level above the median was higher for children who had been breastfed for 4 months or more (adjusted odds ratio (OR) 1.28; 95% confidence interval (CI): 1.02-1.61) and for children who reported cockroaches in their home (OR 1.30; 95% CI: 1.03-1.63). The risk was lower for children whose mother was in paid employment (OR 0.73; 95% CI: 0.54-0.97 compared with those who did not), for children living in homes where gas and electricity were used for cooking (OR 0.45; 95% CI: 0.32-0.62 compared with electricity only) and for children with domestic pets at birth (OR 0.83; 95% CI: 0.70-1.00). There was no association between paracetamol use and serum IgE levels. CONCLUSIONS: Associations between gas fuel use and maternal employment indicate that IgE levels in early life are lower in children who may be living in relative affluence. The discrepancy in the effect of early exposure to pets or cockroaches may reflect differences in these allergens, or be confounded by relative affluence. Further investigation of this cohort will determine how these effects translate into the expression of allergic disease in later life.

Smoke exposure among women in Haiti: the case for improved stoves.

Indoor smoke exposure is responsible for two million deaths per year and has been studied globally, but the impacts of exposure have not yet been evaluated in Haiti, the Western hemisphere's poorest nation. This study measures the disproportionate impact of indoor smoke exposure on the women and children of Haiti. We studied 2296 clinic patients in four Haitian villages to determine the extent of carbon monoxide (CO) exposure, using carboxyhemoglobin saturation in the blood as a proxy for overall smoke exposure. We predicted CO levels to be higher in women, who traditionally perform the majority of cooking duties, and in children who accompany their mothers. CO levels averaged 4.9% in women and 3.4% in men. Women of child-bearing age carried a minimum relative risk (RR) for CO exposure of 1.22, relative to all males and younger females. Older females carried no significant difference in risk. Children averaged the lowest CO exposure among all cohorts. These findings demonstrate the burden of indoor smoke exposure that falls disproportionately on women in these regions of Haiti. Global efforts to mitigate indoor exposure have demonstrated the health, economic, environmental and social improvements that are possible by tackling this problem.

Exposure to open-fire cooking and cognitive performance in children.

We reexamined field data on cognitive performance in light of recent research that shows open-fire cooking--with its emission of harmful substances--to pose a risk to healthy physical development. Tests of three- to nine-year-old children in four communities around the world yielded evidence concerning block-building skills, memory, and the discernment of embedded figures. Naturalistic observations of these children were also undertaken in everyday settings. Open-fire cooking (as opposed to cooking on kerosene stoves) was associated with both lower cognitive performance and less frequent structured play at all ages. Although these correlational results do not reveal causal mechanisms, they are consistent with ideas about negative developmental consequences of exposure to open-fire cooking and suggest that research is needed on the effect on brain development of practices involving production of indoor smoke.

Indoor charcoal smoke and acute respiratory infections in young children in the Dominican Republic.

The authors investigated the effect of charcoal smoke exposure on risks of acute upper and lower respiratory infection (AURI and ALRI) among children under age 18 months in Santo Domingo, Dominican Republic (1991-1992). Children living in households using charcoal for cooking (exposed, n = 201) were age-matched to children living in households using propane gas (nonexposed, n = 214) and were followed for 1 year or until 2 years of age. Fuel use and new episodes of AURI and ALRI were ascertained biweekly through interviews and medical examinations. Household indoor-air concentration of respirable particulate matter (RPM) was measured in a sample of follow-up visits. Incidences of AURI and ALRI were 4.4 and 1.4 episodes/child-year, respectively. After adjustment for other risk factors, exposed children had no significant increase in risk of AURI but were 1.56 times (95% confidence interval: 1.23, 1.97) more likely to develop ALRI. RPM concentrations were higher in charcoal-using households (27.9 microg/m(3) vs. 17.6 microg/m(3)), and ALRI risk increased with RPM exposure (10-microg/m(3) increment: odds ratio = 1.17, 95% confidence interval: 1.02, 1.34). Exposure to charcoal smoke increases the risk of ALRI in young children, an effect that is probably mediated by RPM. Reducing charcoal smoke exposure may lower the burden of ALRI among children in this population.