Car pollution linked to one in six cot death cases

UP to one in six cot deaths may be directly attributable to pollutants from motor vehicle exhaust fumes, research has found.

Scientists discovered clear evidence linking unexplained infant deaths in the United States with sooty particles generated by traffic and power stations.

Their findings indicate that 16% of normal birth weight baby cot deaths can be blamed on the fine particles, known as PM10s.

The pollutants may also be responsible for 24% of all respiratory disease deaths of normal birth weight infants under the age of one, according to the research.

PM10s, which are particles less than 10 micrometers in diameter, have already been shown to cause illness and death in adults.

The international team of scientists looked at death rates among 700,000 infants in 25 US counties between 1995 and 1997, and compared them with background air pollution levels.

Across the counties, which included 23 metropolitan areas, the average all-cause mortality rate was 236.8 deaths per 100,000 infants.

Of these, 14.7 out of every 100,000 could be attributed to PM10 pollution. In the case of unexplained infant deaths, the figure was 11.7 per 100,000 16% of the total.

Three quarters of the cases were from areas which met strict US pollution standards.

The research, led by Reinhard Kaiser from the University of Basel in Switzerland, was published in the online journal Environmental Health: A Global Access Science Source.

The scientists wrote: "Evidence for a causal effect of air pollution on morbidity (illness) and mortality is strong for adults, and evidence is building that air pollution has an effect on infants and young children and a potential impact during the foetal period.

"The evidence needs to be constantly reviewed as further studies become available. Our estimates are based on the best currently available information, leaving considerable uncertainty about the size of the true effect of particulate matter on infant mortality.

"However, given that the whole population is exposed, we conclude that air pollution-related infant mortality is a major public health problem.

"This outcome should be considered in future public health risk assessment and management."

Known risk factors for Cot death, or Sudden Infant Death Syndrome (Sids), include the baby's sleeping position, temperature, and exposure to cigarette smoke.

The Foundation for the Study of Infant Deaths said it was likely that the link between air pollution and cot death was real and not the result of confounding factors in the study.

"The obvious practical message coming out of this work is that these target levels should be lowered further if post-neonatal death is to be reduced beyond existing prevalence levels," the group said.

Consultant paediatrician Professor George Haycock, scientific advisor to the Foundation, said: "It would be difficult to argue against the authors' inference that a reduction in the current recommended acceptable levels of air pollutants is highly desirable.

"The authors were cautious enough not to extrapolate their conclusions to countries other than the USA but it seems highly unlikely that this phenomenon is unique to North America."