Maternal exposure to air pollutants and birth weight in Tehran, Iran

Abstract

Background Air pollution can cause various health outcomes, especially in susceptible groups including pregnant women. Low birth weight (LBW) is among the adverse birth outcomes and is one of the main causes of infant mortality. The aim of this study was to assess the association between air pollutants and LBW in Tehran, Iran. Methods In this case-control study, 2144 babies born in three hospitals of Tehran (Iran) during 2011 to 2012 whose mothers were the residents of this city in last 5 years were considered. Of these, 468 infants with birth weight < 2500 g and 1676 with birth weight ≥ 2500 g were regarded as case and control groups, respectively. Gestational age was also considered for definition of cases (small for gestational age (SGA)) and controls (appropriate for gestational age). Land use regression models were used to assess exposure to particulate matter ≤10 μm in aerodynamic diameter (PM 10 ), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ) and volatile organic compounds (benzene, toluene, ethylbenzene, oxylene, m-xylene, p-xylene (BTEX), and total BTEX) during pregnancy. Logistic regression model was applied to assess the association between air pollutants and LBW. Results The concentrations of air pollutants were very high but similar in cases and controls. After adjustment for potential confounding variables, no statistically significant association was observed between air pollutants and LBW. The adjusted odds ratios (95% confidence interval) for PM 10 , SO 2 , and benzene were 0.999 (0.994-1.005), 0.998 (0.993-1.003), and 0.980 (0.901-1.067), respectively. Conclusions No association was found between LBW and air pollutants. Further studies with more rigorous designs and access to more comprehensive information are suggested to assess the effect of other air pollutants, such as CO, O 3 , PM 2.5 , ultrafine particles, and oxidative potential of particles on birth outcomes.

Functional Kriging for Spatiotemporal Modeling of Nitrogen Dioxide in a Middle Eastern Megacity

“…Our results could benefit epidemiological studies of long-term exposure to nitrogen dioxides in the Middle Eastern megacity of Tehran. Examples of such epidemiological studies are the effect of long-term exposure to air pollutants on the incidence of lung cancer, the air pollutants' long-term effects on low birth weight, and the effect of exposure to long-term multiple pollutants on the incidence of leukemia [50][51][52]. Our long-term exposure model provided not just an updated estimate for the long-term exposure to nitrogen dioxide, but it also provides for the long-term means across all times of the day.…”

Indoor Air Quality in the Most Crowded Public Places of Tehran: An Inhalation Health Risk Assessment

“…In the modern lifestyle, about 90% of a lifetime, on average, spends indoors, and this considerable fact directs the researchers to the development of studies scoping indoor air quality as a crucial issue threatening human health and equipment [4][5][6][7]. There is clear scientific evidence that air pollution poses a significant risk to public health, particularly to vulnerable groups such as children, the elderly, and pregnant women [8,9]. The World Health Organization (WHO) reported that approximately 3.8 million premature deaths were attributed to indoor air pollution each year, and this number contributed to approximately 7.7% of annual mortality [10].…”