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Clean air affects infant weight
Pregnant women who have been exposed to an increased level of air pollution of any kind tend to give birth to children with a lack of body weight, revealed a large-scale international study.
Low birth weight, i.e. when a newborn baby weighs less than 2.5 kilograms, increases the risk of infant mortality and young diseases. In addition, a newborn’s body weight deficit is associated with developmental and health problems later in life, including diabetes and cardiovascular disease.
Scientists have tried before to find out whether exposure to tiny, airborne particles can lead to reduced body weight at birth, but the results have been contradictory.
“A key point in many studies of the effects of air pollution on fetal growth was the haphazardness in the plans of clinical trials, as well as in the methods of assessing the impact,” notes Leonardo Trasande, an expert on environmental health for children.
For the analysis, data were collected on three million newborns from 14 centers in 9 countries, such as the United States, South Korea and Brazil. The study focused on two classes of air pollutants: inhaled particulate matter (PM) less than 2.5 microns (PM2.5) in diameter and less than 10 microns (PM10). These particles enter the atmosphere due to the burning of fossil fuels by enterprises and transport, as well as the burning of wood fuel. They may also contain particles of dust or sea salt.
“Those centers with higher levels of air pollution report an increased risk of birth of underweight newborns compared to health facilities with low levels of atmospheric pollution,” said study author epidemiologist Payam Dadwand of the research center in Barcelona, Spain.
Each increase in PM10 by 10 micrograms per cubic meter (μg m-3) caused a 3 percent increase in the risk of having a baby with a body weight deficit, and the total average weight decreased by 3 grams. The decrease in average weight tripled to 9 grams when the study authors made changes to specific variables, such as maternal age or smoking. In addition, socio-economic status was also taken into account.
Average PM10 values varied in all 14 locations from 12.5 μg m-3 in Vancouver to 66.5 μg m-3 in Seoul. For centres reporting exposure to PM2.5 levels, the likelihood of a newborn underweight increased by 10% with each increase in exposure to harmful substances.
As explained by Leonardo Trasande, at the individual level, the risk is small, but if you take the population as a whole, changing the level of pollution can significantly increase the rate of birth of children with underweight. Smoking, alcohol and drug use, and poor maternal health also negatively affect birth weight.
The study authors also took into account socioeconomic and lifestyle factors that may skew the results. However, in this matter they faced some limitations. Not all centres provided information on whether the mother smoked during pregnancy; data on education and place of residence were used to approximate the socio-economic status of the mother; new exposure to air pollutants during pregnancy was assessed rather than directly measured.
Despite such limitations in the study of these factors, scientists are gaining more evidence that particulate matter is still associated with the condition of the newborn and can affect intrauterine development.
Epidemiologists are concerned that some of the effects of exposure to air pollutants on the mother may not be apparent for several decades of a child’s life. According to the researchers, the current situation with high levels of air pollution in a number of Chinese cities does not bode well. For example, according to the U.S. Embassy in China at the end of January this year, the average PM2.5 per day of observations in Beijing was 460 μg m-3, while the Ministry of Environmental Protection of China reports an indicator of about 350 μg m-3.
The World Health Organization recommends that countries adopt strict air pollution standards by setting annual mean values of 10 μg m-3 for PM2.5 and 20 μg m-3 for PM10. For example, the U.S. Environmental Protection Agency recently raised the standard for PM2.5 from 15 μg m-3 to 12 μg m-3. According to the Agency experts, compliance with these standards will lead to an improvement in the health of the population, which in financial terms will be from 4 to 9.1 billion dollars annually until 2020.
“The impact of air pollution on pregnant women was not taken into account at the time of determining these standards,” said Payam Dadwand. - It's time to think.
Source: /users/104
Low birth weight, i.e. when a newborn baby weighs less than 2.5 kilograms, increases the risk of infant mortality and young diseases. In addition, a newborn’s body weight deficit is associated with developmental and health problems later in life, including diabetes and cardiovascular disease.
Scientists have tried before to find out whether exposure to tiny, airborne particles can lead to reduced body weight at birth, but the results have been contradictory.
“A key point in many studies of the effects of air pollution on fetal growth was the haphazardness in the plans of clinical trials, as well as in the methods of assessing the impact,” notes Leonardo Trasande, an expert on environmental health for children.
For the analysis, data were collected on three million newborns from 14 centers in 9 countries, such as the United States, South Korea and Brazil. The study focused on two classes of air pollutants: inhaled particulate matter (PM) less than 2.5 microns (PM2.5) in diameter and less than 10 microns (PM10). These particles enter the atmosphere due to the burning of fossil fuels by enterprises and transport, as well as the burning of wood fuel. They may also contain particles of dust or sea salt.
“Those centers with higher levels of air pollution report an increased risk of birth of underweight newborns compared to health facilities with low levels of atmospheric pollution,” said study author epidemiologist Payam Dadwand of the research center in Barcelona, Spain.
Each increase in PM10 by 10 micrograms per cubic meter (μg m-3) caused a 3 percent increase in the risk of having a baby with a body weight deficit, and the total average weight decreased by 3 grams. The decrease in average weight tripled to 9 grams when the study authors made changes to specific variables, such as maternal age or smoking. In addition, socio-economic status was also taken into account.
Average PM10 values varied in all 14 locations from 12.5 μg m-3 in Vancouver to 66.5 μg m-3 in Seoul. For centres reporting exposure to PM2.5 levels, the likelihood of a newborn underweight increased by 10% with each increase in exposure to harmful substances.
As explained by Leonardo Trasande, at the individual level, the risk is small, but if you take the population as a whole, changing the level of pollution can significantly increase the rate of birth of children with underweight. Smoking, alcohol and drug use, and poor maternal health also negatively affect birth weight.
The study authors also took into account socioeconomic and lifestyle factors that may skew the results. However, in this matter they faced some limitations. Not all centres provided information on whether the mother smoked during pregnancy; data on education and place of residence were used to approximate the socio-economic status of the mother; new exposure to air pollutants during pregnancy was assessed rather than directly measured.
Despite such limitations in the study of these factors, scientists are gaining more evidence that particulate matter is still associated with the condition of the newborn and can affect intrauterine development.
Epidemiologists are concerned that some of the effects of exposure to air pollutants on the mother may not be apparent for several decades of a child’s life. According to the researchers, the current situation with high levels of air pollution in a number of Chinese cities does not bode well. For example, according to the U.S. Embassy in China at the end of January this year, the average PM2.5 per day of observations in Beijing was 460 μg m-3, while the Ministry of Environmental Protection of China reports an indicator of about 350 μg m-3.
The World Health Organization recommends that countries adopt strict air pollution standards by setting annual mean values of 10 μg m-3 for PM2.5 and 20 μg m-3 for PM10. For example, the U.S. Environmental Protection Agency recently raised the standard for PM2.5 from 15 μg m-3 to 12 μg m-3. According to the Agency experts, compliance with these standards will lead to an improvement in the health of the population, which in financial terms will be from 4 to 9.1 billion dollars annually until 2020.
“The impact of air pollution on pregnant women was not taken into account at the time of determining these standards,” said Payam Dadwand. - It's time to think.
Source: /users/104
