The relationship between intelligence in childhood and risk of alcohol-related diseases and deaths later in life. This was the issue studied by researchers.
The participants were 21,809 Swedish men and women. They were born in either 1948 or 1953. Their intelligence quotient (IQ) was measured in school at age 13.
The database of the ‘Evaluation Through Follow-up’ program was used to track the participants through 2006-2007. Beginning in 1971, alcohol-related diseases and deaths were recorded. The codes used were those of the International Classification of Disease.
The investigators found a significant inverse relationship between intelligence as measured at age 13 and both alcohol-related diseases and deaths. That is, the lower the intelligence, the greater the risk of alcohol-related diseases or death.
The attained socio-economic status (SES) at age 32 was very important. It’s a major factor in explaining the relationship between intelligence and alcohol-related diseases and deaths. This was true for both men and women. The effect of intelligence in childhood may be largely through its effect on later factors. These include educational attainment, occupational status, and income level.
There are various possible explanations for why lower-SES participants tended to experience more alcohol-related diseases and deaths. They include different drinking patterns such as binge versus moderate drinking. Poor lifestyle choices, such as smoking, illicit drug use, and obesity. Less access to high quality health care. And the list goes on.
The SES of participants at age 32 had a much stronger effect on the health outcomes than did the SES of the parents. Thus, people are not fated to suffering alcohol-related disease and death because of accidents of birth.
It is also important to note that there are many weaknesses in the use of IQ tests to measure intelligence.
Source: Sjolund, S, et al. IQ and alcohol-related morbidity and among Swedish men and women. The importance of socioeconomic position. J Epidem Comm Health, 2015, 69, 858-864.