Estonian Schoolchildren Research Articles

The secular rise in IQs: In Estonia, the Flynn effect is not a Jensen effect

This study investigated the secular rise in IQ scores over a 60-year period in 12- to 14-year-old Estonian schoolchildren. In 1934/1936, Juhan Tork adapted the U.S. National Intelligence Test for Estonia and administered it to more than 6000 schoolchildren. We administered the same test to 449 students in 1997/1998 and compared the results of 381 of these with a carefully matched sample of 307 from the testing in the 1930s. We found a rise of nearly 1 S.D. on subtests using basic information-processing algorithms such as Comparison and Symbol–Number, but only 0.50 S.D.s on verbal subtests such as Sentence Completion and Concept Comprehension. The secular gains were most pronounced on the low g-loaded subtests. In two compared age groups of children, the rank order correlations between the secular changes on the various subtests and the rank of those subtests on the g factor are negative and nonsignificant, the mean r s=−.40 (one-tailed P=.13). As such, these results supported Rushton's [Pers. Individ. Differ. 26 (1999) 381] finding that the secular rise over time is not occurring on the g factor. In Estonia, the Flynn effect is not a Jensen effect.

Children’s and Adolescents’ Physical Self-Perceptions as Related to Moderate to Vigorous Physical Activity and Physical Fitness

The aim of this study was to determine the relationship between physical self-perceptions, moderate to vigorous physical activity and physical fitness in Estonian school children and adolescents aged 11–14 years. The sample consisted of 134 boys and 119 girls. Self-perception of body appearance, physical conditioning, sport/athletic competence, strength and general physical self-worth were measured by the Children’s Physical Self-Perception Profile (C-PSPP). Moderate to vigorous physical activity was assessed using 7-day physical activity recall and physical fitness using 20 meter endurance shuttle run. All C-PSPP scales were significantly moderately related with physical activity and fitness in both boys and girls. Boys’ perceptions of strenght competence, physical condition and general self-worth were higher and they participated more in moderate to vigorous activities compared to girls. Multiple regression analysis results indicated the best predictors of moderate to vigorous physical activity and physical fitness were perceived sport/athletic competence, physical self-worth, and perceived strength competence Our results demonstrate that physical self-perceptions are significant correlates of physical activity and fitness in children and adolescents.

Similar prevalence of respiratory symptoms and atopy in Estonian schoolchildren with changing lifestyle over 4 yrs.

The prevalence of allergic sensitization and clinical manifestations is low in Eastern Europe, despite a continuous increase in industrialized countries with a market economy. The aim of the present study was to study changes in the prevalence of respiratory symptoms and atopic sensitization over time among schoolchildren in Estonia, in relation to environmental changes as the country transformed into a market economy. A cross-sectional study of 10-yr-old children was carried out between October 1996 and April 1997, employing a questionnaire regarding the prevalence of wheezing, rhinitis and itching rash (n=979) and skin-prick tests with seven inhalant allergens (n=640). The results were compared with those of a similar study performed in 1992-1993. The 12-month prevalence of wheeze was 8.3%, as compared to 9.4% in 1992-1993 (NS) and of asthma was 2.5 versus 3.2% (NS). The prevalence of a positive skin-prick test result was 14.3% in both studies. Furthermore, the prevalence of sensitivity to the individual allergens was similar, except for a significantly higher prevalence of dog sensitivity in 1996-1997 (4.7 versus 2.0%). The prevalence of respiratory and other potentially allergic symptoms, as well as the prevalence of atopic sensitization, remains low in Estonian 10-yr-old children, despite a changing lifestyle over the past 4 yrs. This could indicate that the time period was too short for environmental changes to affect the prevalence of allergy, or alternatively that risk factors associated with a "western lifestyle" are of particular significance earlier in life.

The Physical Activity of Estonian Primary School Children

The aim of this study was to provide an estimate of the physical activity levels of Estonian primary school children. The subjects were 174 7‐ to 9‐year‐old children (83 boys and 91 girls). Physical activity was assessed by (a) parental seven‐day physical activity recall and (b) Caltrac accelerometers (Hemokinetics Inc., Madison, WI). Caltrac accelerometers were worn between the hours of 8.00 a.m. and 8.00 p.m. during one schoolday and one weekend day and mean activity counts of the Caltrac score for the two days were calculated. According to the results of the seven‐day activity recall, the moderate‐to‐vigorous physical activity (MVPA) levels of the boys were significantly (p<0.05) higher than the girls in all age groups. The 54.2 to 99.4 minutes (9‐year‐old girls and 7‐year‐old boys, respectively) of daily MVPA meet recent Physical Activity Guidelines for Adolescents. The results of the Caltrac monitoring indicated that there were no gender differences in the activity counts of 7‐year‐old children. However, the mean Caltrac scores of the boys were significantly higher than the girls in the 8‐ and 9‐year‐old groups. In addition, the results indicated a significantly (p<0.05) higher level of MVPA in rural compared with urban schoolchildren. It was concluded that the level of MVPA of Estonian primary school children was sufficient to meet recent activity guidelines for adolescents. Boys were generally more physically active than girls of the same age.

The cardiovascular risk factor profile of Estonian school children.

This cross-sectional study was undertaken to assess the occurrence of conventional cardiovascular risk factors in Estonian school children after the socioeconomic changes of the early 1990s. A total of 1018 9-, 12- and 15-y-old randomly selected children were studied for lipid and lipoprotein profiles, blood pressure, weight, height, regular smoking, physical activity and family history of premature cardiovascular disease. In 11-24% of the children, total cholesterol levels were at or above the risk cut-off of 5.2 mmol l(-1), 3-5% of the children were considered to be obese and 6-12% had blood pressure higher than the age- and gender-specific 95th percentile of height. Of the 15-y-old girls and boys, 1% and 10%, respectively, admitted being daily smokers. Five percent of girls and 20% of boys smoked at least once a week. Ten to 18% of children reported little physical activity. According to age groups, 17-25% of the children had a family history of premature cardiovascular disease. The occurrence of three or more risk factors simultaneously characterized only the older age group, in which 2.3% of girls and 3.5% of boys exhibited clustering of potential cardiovascular risk factors. Our findings showed a relatively low frequency of obesity and low mean blood lipid levels with a high proportion of smokers among children in late puberty, implying that preventive efforts should focus on pubertal children to prevent adverse health behaviour.

The cardiovascular risk factor profile of Estonian school children

This cross‐sectional study was undertaken to assess the occurrence of conventional cardiovascular risk factors in Estonian school children after the socioeconomic changes of the early 1990s. A total of 1018 9‐, 12‐ and 15‐y‐old randomly selected children were studied for lipid and lipoprotein profiles, blood pressure, weight, height, regular smoking, physical activity and family history of premature cardiovascular disease. In 11–24 % of the children, total cholesterol levels were at or above the risk cut‐off of 5.2 mmol l‐1, 3‐5% of the children were considered to be obese and 6‐12% had blood pressure higher than the age‐ and gender‐specific 95th percentile of height. Of the 15‐y‐old girls and boys, 1% and 10%, respectively, admitted being daily smokers. Five percent of girls and 20% of boys smoked at least once a week. Ten to 18% of children reported little physical activity. According to age groups, 17‐25% of the children had a family history of premature cardiovascular disease. The occurrence of three or more risk factors simultaneously characterized only the older age group, in which 2.3% of girls and 3.5% of boys exhibited clustering of potential cardiovascular risk factors. Our findings showed a relatively low frequency of obesity and low mean blood lipid levels with a high proportion of smokers among children in late puberty, implying that preventive efforts should focus on pubertal children to prevent adverse health behaviour.

Radiographic findings in the teeth and jaws of 14- to 17-year-old Estonian schoolchildren in Tartu and Tallinn

Panoramic radiographs were taken of 392 Estonian schoolchildren (33% boys and 67% girls) aged 14-17 years, 197 in Tam and 195 in Tallinn. The mean number of permanent teeth was 31.5. In 14% of the children one to four teeth (excluding wisdom teeth) were missing. The frequencies of missing wisdom teeth and supernumerary teeth agreed with those in the literature, being 17% and 3%, respectively. The mean number of radiographically detected carious teeth was 1.9 in Tartu and 3.3 in Tailinn. Secondary caries was common, being found radiographically in half of the schoolchildren. Endodontic treatment had been given to 13% of the subjects in Tartu and to 46% in Tallinn, the success rates being 47% and 44%, respectively. The percentage of radiographic signs in the mandibular condyles of girls (5%) was greater than that of boys (1%). Changes in the maxillary sinuses were found in 16% of the children. Eight dontogenic cysts, one cyst of the incisal canal, and one solitary bone cyst were found. Tumors included two odontomas, two cemento-ossifying lesions, and one osteoma in the maxillary sinus. The health status of the jaws of the Estonian schoolchildren was considered to be fairly good.

Prevalence of bronchial hyperreactivity as determined by several methods among Estonian schoolchildren.

There is a lack of established criteria to identify asthma and bronchial hyperreactivity (BHR) in epidemiological studies, although both conditions appear to bear some relationship to atopy, at least in children. Recent studies indicate a low prevalence of atopy in former Socialist countries in Europe, yet the prevalence of BHR has been reported to be high. We have analysed the relationship between the outcome of various lung function tests, atopy and clinical symptoms of bronchial asthma in an epidemiological survey of Estonian 10-12 year old schoolchildren. Metacholine provocation test (four steps with the cumulative doses 100, 300, 700 and 1100 micrograms), exercise challenge test and PEF-variability over two weeks were done in 806 children in Tallinn (coastal, industrialised city) and 774 children in Tartu (inland, university town). A positive response to the metacholine challenge test was recorded in 19% in Tallinn and in 32% in Tartu (p < 0.001). A similar tendency was observed for a more than 15% decrease of FEV1 in the exercise challenge test, i.e. 6% in Tallinn and 18% in Tartu. There was only a weak relationship between BHR, as defined by either a positive metacholine challenge and/or exercise test, diagnosed asthma and reported wheezing. Thus, 47% of the wheezing children and 30% of the children with asthma had negative test results. Only 17% of the children with a positive metacholine challenge were atopic, as defined by at least one positive skin prick test. In conclusion, none of the methods employed to assess bronchial hyperresponsiveness were very useful for the identification of wheezing and asthmatic children in this epidemiological study. In contrast to the results of studies in Western Europe, most children with bronchial hyperreactivity in Estonia are not atopic.

Dental health in 14- to 17-year-old Estonian schoolchildren in Tartu and Tallinn.

The dental health of 392 Estonian schoolchildren aged 14-17 years (197 in Tartu and 195 in Tallinn) was studied. In Tartu only 1 child had lost teeth because of caries, as against 30 in Tallinn. Clinically caries-free dentitions were found in 15% of the children in Tartu and in 3% in Tallinn. The mean DMFT value was 3.7 in Tartu and 7.0 in Tallinn, being higher among girls in both cities. The mean DT value was 1.0 in Tartu and 2.6 in Tallinn. All subjects examined had a gingival bleeding index (GBI) higher than zero. The mean GBI was 20% in Tartu and 18% in Tallinn.

327 THE RESULTS OF VARIOUS LUNG FUNCTION TESTS AMONG ATOPIC AND NON-ATOPIC ESTONIAN SCHOOLCHILDREN

Four-step methacholine provocation test (cumulative doses of methacholine, respectively 100, 300, 700 and 1100 μg), exercise challenge test and assessment of peak expiratory flow variability (four times daily for two weeks) were used in the cross-sectional study in order to reveal the prevalence of bronchial hyperreactivity among the Estonian schoolchildren. The study included 458 children from Tallinn (industrialized capital, situated on the cost) and 653 children from Tartu (inland, university town) aged 10-12 years. The prevalence of positive skin prick test was 13% in Tallinn and 8.3% in Tartu. Surprisingly the number of positive responses in the methacholine challenge tests was significantly higher in Tartu than in Tallinn (31% and 19% respectively). Similarily, decrease of FEV1, value more than 15% was observed in exercise challenge tests (18% and 6% respectively). There was a good correlation between the data obtained in the methacholine and exercise challenge tests (p=0.006). The findings show that other factors than sensitization to allergens are important for bronchial hyperreactivity.