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M Koiranen

Publications and source records attributed to M Koiranen.

4 recordsLinked to original sources
PubMed1992

Association of perinatal events, epilepsy, and central nervous system trauma with juvenile delinquency.

The association of perinatal events, childhood epilepsy, and central nervous system trauma with juvenile delinquency was studied prospectively in a geographically defined population of 5966 males in northern Finland. Those who had obtained a criminal record up to the age of 22 years, totalling 355, or 6.0%, were defined as delinquents. The incidence of delinquency was not increased in males with a birth weight less than 2500 g or greater than 4000 g, preterm births < 37 weeks' gestation, or those with perinatal brain damage or having epileptic seizures before 14 years of age. The incidence was increased by 6.8% in the group of males with birth weights less than 3500 g, but not significantly increased after standardisation for a number of social and demographic background variables. The incidence was increased by 10.3% among the males who had had a central nervous system trauma by the age of 14 years, however, and this factor remained significant when social and demographic factors were standardised by regression analysis, with an odds ratio of 1.9 for all males with a criminal record and an odds ratio of 3.15 for those who had committed a violent crime. Previous central nervous system trauma may be a cause of delinquency, or another possibility is that the type of behaviour pursued by males who are likely to commit a violent crime will expose them more often to accidents which can result in central nervous system trauma.

Adolescent↗
PubMed1991

Fitting mixture models to birth weight data: a case study.

Birth weights by gestational age are compared in two birth cohorts from Northern Finland, the first from 1966 and the second from 1985-1986. A curious fact in the data is that mean birth weight before the 39th week was lower in the latter series although the mean birth weight for the total series was higher. Similar findings have been reported in other series. A mixture model with the nonparametric regression function is proposed for studying the hypothesis that the difference was caused by more frequent gross errors in gestational assessment in the earlier cohort. The probability of an error in gestational assessment then greatly depends on the observed gestational age, which makes the mixture model nonstandard. Maximum likelihood solutions to the parameters in the proposed model were computed employing the general expectation-maximization (EM) algorithm. A technique for studying the effect of errors on the intrauterine weight gain curve is proposed and applied to our two birth cohorts. The risk of underestimation of gestational age seems to be larger in the previous series and the differences between the growth curves almost totally vanish when "corrected" by means of the mixture model.

Algorithms↗
PubMed1987

Neurological handicaps among children whose mothers smoked during pregnancy.

Neurological handicaps among children up to age 14 whose mothers had smoked during pregnancy (N = 1,819) and control children born in Northern Finland in 1966 were studied. Altogether, 78 children of smokers and 62 controls had mental retardation (IQ less than 85), cerebral palsy, and/or epilepsy, either current or past. Neither the number of handicapped children nor the numbers of the various handicaps differed significantly with respect to maternal smoking, although the figures were higher among smokers. The children of the smokers had perinatal diseases and conditions known to cause long-term neurological sequelae significantly more often, but the actual number of such cases did not increase. Mortality up to the age of 14 years was statistically significant among children born to smokers.

Adolescent↗