Prenatal exposure to Hong Kong flu associated with reduced intelligence in adulthood

"Prenatal exposure to Hong Kong flu associated with reduced intelligence in adulthood | AboutHK.Com - more information about HK"

The Hong Kong influenza pandemic was responsible for more than 700,000 deaths worldwide in the late 1960s, with major outbreaks of diseases in Europe in the winter 1969-1970. A number of studies have been conducted to determine whether prenatal exposure to the influenza virus can lead to mental disorders that affect a small proportion of the population, but no studies have investigated the possible effects of prenatal exposure on intelligence in the middle of the general population. A new study published in the Annals of Neurology that the early prenatal exposure to the Hong Kong flu may be interfered with fetal development and cerebral causes reduced intelligence in adulthood. The study involved records of more than 180,000 men born between 1967 and 1973 who served in the military. Military service is for young men in Norway, which will be evaluated medically and psychologically before they enter the service. The intelligence test data used in the study consisted of a composite outcome of arithmetic, word and figures similarity tests similar to those in intelligence tests. The results showed that average earnings increased intelligence in each birth year from 1967 to 1973, except for a downturn in 1970. The intelligence scores of men born in the July-October of this year, six to nine months after the outbreak of the Hong Kong flu in Norway, were lower than the mean values for those born in the same months during the previous and following years. The mean result of the intelligence men born in these months was also lower than the average of men born in any other month of the year 1970, and this trend was not seen in other years. Since the flu outbreak during the winter months, this means that the exposure during the first three to four months of pregnancy seems to have the strongest effect on intelligence scores. “This is the first report of a possible association between prenatal exposure to an influenza virus epidemic and the mean level of intelligence in the general population,” said Dr. Willy Eriksen of the Norwegian Institute of Public Health, co-author of the study. The authors note that other types of infections of the mothers during pregnancy such as rubella, varicella, cytomegalovirus and toxoplasmosis can cause central nervous system disorders and cognitive delay in children. In these cases, severe damage to the fetal brain also contributes to the first trimester. There are several possible explanations for the results of the study. It may be that exposure to the influenza virus affects the brain development of fetuses, as in laboratory animals. Also some influenza virus strains, including the Hong Kong flu virus can be controlled through the placental barrier, it is possible that some fetuses with a cerebral infection. It is also possible that a maternal infection during pregnancy has an influence on the fetal brain by maternal immune response or high body temperature, or on medications for the treatment of infections. The authors point out that if 20 percent of men born in July-October 1970 were with the flu virus, and assuming they were all affected neurological, prenatal exposure to such a virulent virus can intelligence results from three to seven points on a standard IQ scale. “If cerebral complications occurred in only a small group of those who were exposed, however, the effects on the intelligence of the susceptible individuals may have been considerably larger,” says Eriksen. Comments Please login to post comments or replies.