Browsing by Author "Silvo, Jenni"

Objectives: Low birth weight has been associated with impaired cognitive abilities especially in childhood and young adulthood. However, the role of a low Apgar score on cognitive functions remains unclear. Apoliprotein E (APOE) gene allele ε4 has been linked to older people’s cognition, but the influence of APOE alleles on cognition of children or middle-aged is not well understood. The present study investigated the effects of low birth weight (< 2000 g) and low Apgar scores (< 7) on later cognitive performance and on the stability of cognitive functions from childhood to middle age. In addition, the influence of APOE ε2 and ε4 alleles on risk group subjects’ cognitive performance was evaluated. It was hypothesized that the groups with perinatal risk factors have impaired cognitive abilities in all the domains and have lower stability within these abilities compared to controls. Low birth weight was hypothesized to contribute lower cognitive abilities more than a low Apgar score. It was also assumed that APOE ε4 allele impairs cognitive performance only at midlife, not in childhood. Methods: The subjects with low birth weight (n = 66) and/or a low Apgar score (n = 60) were selected from a birth cohort born during 1971–1974. The control subjects (n = 95) were free from perinatal risk factors. Cognitive performance was evaluated using Wechsler’s intelligence test. All the subjects completed the test at the age of 40 (n = 221) and some also at the age of 9 (n = 190). The differences between the groups were computed with the analysis of covariance, where family socioeconomic status was controlled. Differences in the stability of cognitive abilities were evaluated with repeated measures ANOVA and correlation analysis. The effect of APOE ε2 and ε4 alleles on cognitive performance was computed with t-test. Results and conclusions: The subjects with low birth weight reached lower scores in all the cognitive domains compared to controls. At midlife, there was also a trend towards lower general intelligence in individuals with a low Apgar score. The lowest stability in cognitive performance between childhood and middle-age was observed among those born with a low birth weight. However, the difference in the stability was not significant between the groups. APOE ε4 allele was related to lower ability of perceptual reasoning in childhood and middle age. According to the results, the effects of low birth weight on cognitive functions seem to extend to middle age. However, it is assumed that environmental factors have an important role in later development in people with low birth weight. Based on the results, the APOE ε4 allele might impact already on early cognitive development. In the future, it is important to examine if this initial impairment in perceptual reasoning is related to abnormal aging among those with APOE ε4 allele.