[Show abstract][Hide abstract] ABSTRACT: This study examined the association between infant developmental milestones and educational level at 31 years of age in the Northern Finland 1966 Birth Cohort (n = 12 058). Developmental data (age at standing, walking, speaking, and measures of bowel and bladder control) were gathered from children's welfare centres. Information on type of schooling at 14 years of age was reported by children and parents. School achievement at 16 years of age and educational level at 31 years were obtained from national registers. Those who reached infant developmental milestones sooner in their first year of life had significantly better (p < 0.05) mean scores in teacher ratings at 16 years, and at 31 years they were more likely to have achieved a better educational level than slower developers. The adjusted odds ratios for individuals who developed more slowly to remain at a basic educational level (7 to 16y) ranged significantly from 1.1 to 1.3. The possibility of advancing from secondary to tertiary level was 1.4 times greater in faster developers than in slow developers. In conclusion, those who develop faster during their first year of life tend to attain higher levels of education in adolescence and adulthood.
Full-text · Article · Oct 2005 · Developmental Medicine & Child Neurology
[Show abstract][Hide abstract] ABSTRACT: Data on the birth weight-blood pressure relationship are inconsistent. Although an inverse association has been suggested in several large studies, interpretation is complicated by publication and other biases. Few data are available on the relationship between other early growth measures and blood pressure. We examined the shape and size of association between determinants of fetal growth, size at birth, growth in infancy, and adult systolic and diastolic blood pressure at 31 years in the prospective northern Finnish 1966 birth cohort of 5960 participants. Birth weight, birth length, gestational age, ponderal index, and birth weight relative to gestational age showed a significant inverse association with blood pressure at age 31. Rapid growth in infancy ("change-up") was positively associated with blood pressure. Adjusted regression coefficients for birth weight indicated systolic/diastolic blood pressure lower by -1.7 (95% confidence interval [CI], -2.5, -1.0)/-0.7 (95% CI, -1.4, -0.02) mm Hg for 1 kg higher birth weight. The significant inverse association between birth weight and systolic blood pressure persisted without adjustment for adult body mass index for males. Among females, gestational age showed a stronger association with blood pressure than birth weight: gestational age higher by 7 weeks (equivalent to an average of 1 kg higher birth weight) among singletons associated with -2.9 (95% CI, -4.7, -1.1) mm Hg lower systolic blood pressure. Our results support the concept that birth weight, other birth measures, and infant growth are important determinants of blood pressure and hence cardiovascular disease risk in later life.
[Show abstract][Hide abstract] ABSTRACT: Central nervous system (CNS) viral infections have been suggested to increase the risk of schizophrenia, although most of the evidence is indirect and comes from rather few studies on exposure to various infections in general. In the Northern Finland 1966 Birth Cohort the association between schizophrenia and other psychoses and childhood CNS infections has been analysed, and in this paper we present the follow-up results up to the end of 1994 and 1997. Data regarding the infections were collected prospectively between 1966-1980 and data on psychoses from 1982. The registered psychiatric diagnoses were validated using the DSM-III-R classification. Out of the 11017 subjects (96% of all births in that year) 145 had suffered a CNS infection during childhood, which in 102 cases was a viral infection. In the follow-up to the end of 1994, 76 had schizophrenia, and their number increased to 100 to the end of 1997. In addition, up to the end of 1994, 52 patients had a non-schizophrenic psychosis. Four cases in the schizophrenia patient group and none of the patients with other psychosis had suffered a viral CNS infection. None of the schizophrenia cases and two of the patients with other psychosis had had a bacterial infection. The adjusted odds ratio for schizophrenia after a viral CNS infection was 4.8 (95% confidence intervals [CI] 1.6-14.0) in the follow-up to the end of 1994 and 2.5 (0.9-7.0) in the follow-up to the end of 1997. The clinical course variables did not differ between the schizophrenia patients with or without CNS infection. Our results suggest that viral CNS infections during childhood may have a role as a risk factor for schizophrenia. Their role may be modest at the population level due to their relative rareness.
No preview · Article · Mar 2004 · European Archives of Psychiatry and Clinical Neuroscience
[Show abstract][Hide abstract] ABSTRACT: A cohort study of 12,000 persons with a follow-up period ranging from birth to the age of 28 years.
To determine the cumulative incidence of lumbar disc disease leading to hospitalization in a well-defined geographic population, with special emphasis on age of onset and differences between the genders and among disease categories.
There are few published reports on low back pain in adolescence, and most of them are cross-sectional in design.
The Finnish National Hospital Discharge Register was used to identify all possible cases of lumbar disc disease. Copies of all hospital records regarding the diagnosis and course of the disease were collected and the hospitalizations were classified into three categories: 1) confirmed herniated nucleus pulposus (HNP), 2) unconfirmed HNP (sciatica symptoms without visible herniation), and 3) other low back diseases. The patients were classified according to the highest category of diagnosis achieved by each.
Symptomatic low back pain leading to hospitalization first appeared around the age of 15 years, and the incidence rose more sharply from the age of 19, especially in men with other low back diseases. Men were hospitalized more than twice as often as women.
Lumbar disc diseases leading to hospitalization begin early.
[Show abstract][Hide abstract] ABSTRACT: We followed 11,355 children born in 1966 up to the age of 24 years to investigate the impact of birthweight on long-term outcomes of death and development. As expected, low-birthweight (LBW, 1500-2,499 gm) children showed a higher risk of death than normal-birthweight (NBW, greater than or equal to 2,500 gm) children before the age of 15 years. Rate ratios for LBW children ranged from 25 for the first week of life to 2.5 for ages 5-14 years. Rate ratios of very-low-birthweight (VLBW, <1,500 gm) children for the first year of life were 10 times higher than those of LBW children. Similarly, for the first 14 years of life, surviving LBW children experienced a higher risk of being hospitalized as well as staying in hospitals for over 2 weeks if they were hospitalized. The LBW children still had a higher risk of receiving sick pensions at the age of 24 years.
[Show abstract][Hide abstract] ABSTRACT: The sex difference in perinatal mortality in developed countries is largely unexplained. The current study evaluated the differences in the impact of maternal smoking during pregnancy on the risk of perinatal death between males and females. The analysis involved 11,469 and 9,404 newborns derived from two population-based birth cohorts in Northern Finland, for 1966 and 1985-86, respectively. The perinatal mortality rate was 23 per thousand in the 1966 cohort and 9 per thousand in the 1985-86 cohort. The rate ratio (RR) for mortality for males over females is 1.15 and 1.60 in the two cohorts, respectively. Among children whose mothers smoked during pregnancy, the RR was 2.2 (95% CI 1.0, 4.7) for the former cohort and 4.8 (95% CI 1.5, 15.2) for the later cohort; and among the children whose mothers did not smoke the corresponding RR was 1.2 (95% CI 0.9, 1.6) and 1.1 (95% CI 0.6, 1.9). Maternal smoking during pregnancy could be an important determinant accounting for the excess perinatal death for males over females. Our results encourage evaluation of the findings among other populations.
[Show abstract][Hide abstract] ABSTRACT: The 1966 North Finland general population birth cohort was studied to determine whether abnormalities during pregnancy, delivery, and the neonatal period are associated with adult-onset schizophrenia.
The authors included all 11,017 subjects alive in Finland at age 16. For each individual, standardized assessments made during pregnancy, delivery, and infancy were linked to national psychiatric case registers covering the period up to age 28. Subjects with DSM-III-R schizophrenia were identified by using a two-stage screen that included perusal of individual case records. Associations (adjusted odds ratios) between schizophrenia and specific pregnancy, delivery, and neonatal characteristics were calculated.
Within this cohort, 76 cases of DSM-III-R schizophrenia arose by age 28 years; 51 (67.1%) of these persons were men. Demographic characteristics and previous obstetric histories of the mothers were similar in the case and unaffected comparison groups, although the former were more likely to have been more depressed than usual during pregnancy. Low birth weight (< 2500 g) and the combination of low birth weight and short gestation (< 37 weeks) were more common among the schizophrenic subjects. Being small for gestational age (< 10th percentile) was not more common. Of 125 survivors of severe perinatal brain damage, six (4.8%) later developed schizophrenia.
The spectrum of adverse outcomes after fetal and perinatal insults unfolded beyond childhood and included adult-onset schizophrenia. The findings have implications for understanding the mechanisms involved in the development of schizophrenia and, possibly, for its prevention.
Preview · Article · Mar 1998 · American Journal of Psychiatry
[Show abstract][Hide abstract] ABSTRACT: Although a developing country, China has a lower occurrence of low birth weight (LBW) than many developed countries. This study of two population-based one-year birth cohorts, from Finland in 1985-86 and China in 1992, shows the occurrence of low birth weight (LBW) (1000- < 2500 g) among singletons to be 2.6 percent in the Chinese cohort and 3.0 percent in the Finnish one, and that of preterm births (28- < 37 weeks) 2.7 percent and 4.5 percent, respectively. The main component of LBW is term LBW (57.4 percent) in the Chinese case and preterm LBW (64.7 percent) in the Finnish case. The perinatal mortality rate (PMR) was twice as high in the Chinese cohort (13.0 vs. 5.9 per thousand). The occurrence of LBW in the Finnish cohort decreased to 2.3 percent after crosstabulation of the Finnish mothers to conform in structure to the population of Chinese mothers in terms of maternal age, marital status and maternal smoking. The result suggests that the lower incidence of LBW in the Chinese cohort seems to be a reflection of the Chinese socio-cultural environment, which provides Chinese mothers with favourable characteristics. The Finnish excess LBW would have disappeared if the mothers had possessed those characteristics as well. The excess perinatal deaths in the Chinese series might be explained by the different levels of perinatal health care in the two countries.
No preview · Article · Mar 1998 · Scandinavian journal of social medicine
[Show abstract][Hide abstract] ABSTRACT: This study describes patterns of sex differentials in perinatal mortality in China and Finland. The analysis is based on three population-based one-year birth cohorts, one from Qingdao, China, in 1992 and two from Northern Finland in 1966 and 1985-86, comprised of 9,219, 11,422 and 9,207 singletons with at least 28 gestational weeks and 1000 g in birthweight, respectively. Both Finnish cohorts had an excess of male over female perinatal deaths, but in the Chinese cohort girls were more likely to die than boys. The adjusted odds ratio (OR) of perinatal mortality for boys was 1.31 (95 per cent confidence interval [CI] 0.98, 1.78) and 1.57 (95 per cent CI 0.89, 2.78) in the Finnish 1966 and 1985-86 cohorts, respectively, and 0.82 (95 per cent CI 0.55, 1.20) in the Chinese cohort. The corresponding figure for stillbirths in the Chinese was 0.57 (95 per cent CI 0.33, 0.98), which could explain the total excess of female deaths during the perinatal period. Our results suggest that the role of different social and cultural environments on the existing sex differentials in perinatal mortality between the countries needs further evaluation.
[Show abstract][Hide abstract] ABSTRACT: The association between hearing impairment in adolescence and school performance and the outcome of education was studied among 25-year-old subjects followed since pregnancy in the Northern Finland birth cohort. The series, 395 subjects with abnormal hearing and 977 randomly selected controls, was based on a questionnaire on hearing and school achievement sent to 11780 members of the cohort alive at the age of 14 years, and on audiometric screening test requested from health centers. Hearing loss was defined as 'clinically significant' if the pure tone average (PTA; mean of the thresholds at 0.5, 1 and 2 kHz) exceeded 25 dB in the better ear; a threshold of > or = 30 dB at 4 kHz and a PTA of < or = 25 dB as '4 kHz loss'; and as 'slightly abnormal' if any of the thresholds exceeded 20 dB at any frequency and the case did not belong to the above two categories. The more severe the hearing impairment, the poorer was the child's performance at elementary school. Those with normal hearing and those with a slightly abnormal or 4 kHz loss were equally often accepted for intermediate education (88%), while those with a clinically significant loss had the lowest acceptance figures (64%). When adjusting for neurological and social confounders, excluding mental disability, the risk of not qualifying from intermediate or higher education at all was twice as high among those with a clinically significant loss as among the controls (OR 2.1, 95% CI 1.13-3.8), and was still elevated after adjustment had been made for all the relevant perinatal, neurological and social factors (OR 1.9, 95% CI 1.02-3.6). 14% of those with a clinically significant hearing loss, 9% of the subjects with a 4 kHz loss and 7% of those with normal hearing were unemployed at the age of 25 years. Hearing impairment appears to have effects on both the outcome of education and employment status.
No preview · Article · Jul 1997 · British Journal of Audiology
[Show abstract][Hide abstract] ABSTRACT: This multilevel study of spatial variability in, and determinants of, birthweight was conducted using individual and ecological data in a geographically defined prospective birth cohort for 1986 in northern Finland. The study area comprises three large areas defined by latitude: Northern Lapland (NL), Southern Lapland (SL) and Oulu province (OP), comprising 74 localities with a total study population of 9216 singleton births. The mean birthweight was 3482 g for NL, 3537 g for SL and 3587 g for OP (NL vs. OP and SL vs. OP: P < 0.05). The crude rate for stillbirths was highest in NL. The women in the northernmost area were socially less privileged and the localities less prosperous compared with those in the southernmost area. Significant spatial clustering of mean birthweights was found (P = 0.0016), with highest birthweight in the south-western part of the study area. A variable expressing the wealth of each locality, the financial capacity category (FCC), had its lowest mean value in NL, with a range of one to six for the localities studied here. A multilevel multiple regression model showed that, after allowing for sex, gestational age, mother's age, height and hypertensive disorders, parity, body mass index, previous low birthweight child and smoking as individual determinants of birthweight, part of the residual variation could be explained by the locality wealth parameter. Using the multilevel model, the differences in mean birthweight across the three latitude areas persisted but were reduced (difference OP vs. NL reduced from 105 g to 86.5 g). The relationship between birthweight and FCC was inverse U-shaped with the highest mean birthweight estimated for localities occurring in the middle of the range (FCC = 3). The wealthiest urban localities (FCC = 6) and the most deprived localities (FCC = 1) both had a predicted birthweight about 60 g below the maximum at FCC = 3, if all other factors were held constant. This result, taken together with the spatial clustering of birthweights, suggests that there may be important social and environmental determinants of birthweight that have yet to be identified.
No preview · Article · Jul 1997 · Paediatric and Perinatal Epidemiology
[Show abstract][Hide abstract] ABSTRACT: In a sample from the unselected, general population Northern Finland 1966 Birth Cohort, 11017 individuals alive at the age of 16 years were studied until the age of 27. The cumulative incidence of early onset schizophrenia until 23 years was higher (1.14%; 9/792) among young persons from the highest social class or class I (determined according to father's occupation) than among children from lower social classes (0.47%; 48/10225), the difference being statistically significant (p < 0.05). The incidence of schizophrenia in the highest social class was higher than expected among girls, firstborns, children of young mothers under 30 and urban residents (p < 0.05) compared with lower social classes. When cases from the highest and other social classes were compared, there was no clear difference in background factors or clinical course. Four alcoholics, one of them also schizophrenic, were found among nine social class I fathers. The results suggest that in some families in Northern Finland, a father's professional advancement, often linked to mental disorder, may be one determinant of an increased risk of schizophrenia in the child.
No preview · Article · Mar 1997 · Schizophrenia Research
[Show abstract][Hide abstract] ABSTRACT: This study reports the use of psychotropic drugs and pregnancy outcome in a prospective survey carried out in northern Finland in 1985-1986, consisting of 7933 pregnant women and their 8030 births. Of the mothers, 120 (1.5%) used psychotropic drugs during pregnancy and of them 26 (0.3% of the total) used these drugs before and during the pregnancy. According to the logistic regression analysis, the biological and social background variables associating significantly with the use of these drugs were maternal advanced age and multiparity (> 35 years and > 4 parous), overweight (body mass index > the 90th percentile), smoking, alcohol use, belonging to social class IV, and failure to ensure contraception. The users needed hospital observation significantly more often during pregnancy (regular users, 80.8%; occasional users, 38.3; nonusers, 27.4%) and the adjustment of the background variables did not change this result. Of the pregnancy complications bleeding was significantly more common among users than nonusers (23.3 vs. 13.2%) and this difference was not explained by difference in background variables. The mean birth weight of infants of the regular users was significantly lower (255 g) when background variables were standardized by linear regression analysis. No association of increased number of birth defects was found with usage of psychotropic drugs.
No preview · Article · Nov 1996 · Journal of Clinical Epidemiology