[Review of epidemiological studies on individual and environmental risk factors in the aetiology of congenital heart defects].

INTRODUCTION: among all congenital malformations, congenital heart defects (CHDs) are the main cause of neonatal mortality and infant mortality and morbidity, thus representing a major public health burden. Several epidemiological studies suggested the role of environmental factors in the genesis of CHDs.

OBJECTIVES: to collect the recently literature (2011-2015) on the increasing risk of CHDs in the offspring of exposure to industries, mines, landfills, and incinerators and individual risk factors (cigarette smoking, alcohol use, occupational exposure, socioeconomic status, and air pollution).

DESIGN AND METHODS: a search was carried out in PubMed following SENTIERI project criteria to evaluate evidence by selecting English and Italian articles regarding human studies. 2,066 abstracts were collected and examined individually. Systematic reviews of epidemiological and individual studies reporting association estimates between the outcome (CHDs) and at least one of the risk factors were selected.

RESULTS: studies on industries and landfills exposures provided limited evidence of increased risk of CHDs associated with the proximity of maternal residence to the sites. Inadequate evidence was found for positive association between exposure to mines or incinerators and risk of CHDs. Regarding maternal cigarette smoking, literature provided sufficient evidence of an increased risk of CHDs in offspring. A limited evidence of an increased risk of CHDs among pregnant women working in agriculture or exposed to solvents and polycyclic aromatic hydrocarbons emerged. Sufficient epidemiological evidence emerged for the association between CHDs and maternal exposure to high concentrations of NO2 and SO2.

CONCLUSIONS: meta-analysis results should be interpreted with caution as they are based on a few studies, some of which are subject to high heterogeneity. For future research, epidemiological studies including spontaneous abortions and voluntary termination of pregnancy, an accurate individual exposure characterisation and an adequate control of the main confounding variables are needed.