Children and the risk of autism

Research on birth records of more than 7 million children born in California, USA, in the 1990s and early 2000s found a clear link between a child conceived in the winter cold and the risk of autism in the future .

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Of the 7 million children in the study, children who were conceived during the cold winter months will certainly be at a higher risk of autism, according to the researchers. The risk of having an autistic child grows during the fall and winter until early spring, and children who are conceived in March will be at higher risk for autism 16 % when compared to children who were conceived in July.

(Artwork: Futurity)

Researchers found that environmental factors such as exposure to seasonal influenza viruses, can play an important role, as an autism agent in children who receive it. pregnancy during the cold winter months every year.

The results of this study are published online in the journal The journal EPIDEMIOLOGY , issued on May 4, 2011.

" Research results are obtained after screening for factors such as mother, race or ethnicity, and the year the child is conceived, " says Ousseny Zerbo, author and home. Top research, a fifth-year graduate student in the epidemiology research group, works at the Department of Public Health Sciences, School of Medicine, UC Davis University, USA.

In this study, researchers obtained more than 7,200,000 records of children born between January 1990 and December 2002 from the California Office of Civil and Medical Data, California, USA. Researchers have excluded some records of children who died before reaching the age that is often diagnosed: Suffering from autism.

Other records are excluded because these records do not contain information that calculates the exact and complete month of adoption. The month of conception is calculated as follows: the last day of the mothers' menstrual period reporting plus the next two weeks.

Dr. Irva Hertz-Picciotto, UC Davis University, USA

The total number of qualified records in this study is about 6,600,000 records, accounting for 91% of the 7.2 million children born according to the data recorded during the study period. These children will be monitored until their 6th birthday, to determine if these babies will develop autism.

Researchers identify children diagnosed with autism by comparing these birth records with children receiving services from the Department of Services Development (DDS), California, USA . About 19,000 autism cases have been recorded, identified as " full syndrome " autism , according to DDS records.

Research shows overall: The risk of a child's autism increases gradually if this child is conceived during the period: from month to month during the winter until March . According to this study, winter is considered December, January and February. Each month is compared with July, with the incidence of autism increasing by 8% higher in children who are conceived. In December, even this rate increased to 16% higher in children who were conceived in March.

Previous studies have found a link between: The risk of autism in children and the month of conception or birth, giving different results. For example, studies conducted in Israel, Sweden and Denmark have found an increased risk of autism for children born in March. In contrast, studies were conducted. In Canada, Japan, the United States and the United Kingdom before, identified the risk of increasing autism in children born in the spring. However, these studies have so far been carried out on a smaller scale, almost only a few hundred cases of autism, when compared to 19,000 cases of autism identified in California. , USA.

" Studies of seasonal changes may provide clues to some of the underlying causes of autism. Based on this study, it is possible to achieve efficacy to pursue exposure to similar models. self-seasons, such as: infection and mild malnutrition ", according to Irva Hertz-Picciotto, head of the occupational health and environmental department, working at the Department of Public Health Sciences, Medical and University Schools. Study at UC Davis, USA.

" However, it is possible that the development of autism is not due to the time when the child is conceived. Rather, it may be due to exposure to some toxic substance, in 3rd month of pregnancy, or in the 2nd quarter , "herz - Picciotto says, is a Researcher associated with UC Davis Institute of MIND, USA. " If so, we may need to seek high-risk exposure that occurs several months after conception. For example, with an allergen, it often appears in the spring and early peaks. summer . "

Researchers say the study is a starting point for additional investigations. By the occurrence of seasonal autism, it may be because of other causes including: the ability to expose pesticides, chemicals people use indoors to control insects during rainy months or months warm, and chemicals that have been used in agricultural activities.

Other authors of this study include: Maria iosif, Lora Delwiche and Cheryl Walker, working in the Department of Public Health Sciences, School of Medicine, Davis UC University, USA.