Diverging prevalence trends of atopic disorders in Norwegian children. Results from three cross-sectional studies

BACKGROUND

During the last decades there has been extensive epidemiological research to explore the increasing prevalence of asthma and allergy in childhood. The worldwide variations in prevalence of these diseases necessitate regional rapports. Furthermore, time-trend analyses with comparable methods are important in order to monitor the rapidly changing prevalence of these diseases.

METHODS

Three cross-sectional questionnaire-based studies of asthma and allergy in schoolchildren were conducted in the counties of Troms and Finnmark, in northern Norway in 1985, 1995 and 2000. The two former studies included children from randomly selected primary schools (n = 1794/1985, n = 1432/1995). The latter study was a part of ISAAC-II Europe study (n = 3853). Identical items of asthma and allergy were employed. The analyses comprised only children 9-11 years of age.

RESULTS

The prevalence of asthma was 9.3, 13.2 and 13.8% in 1985, 1995 and 2000, respectively. However, great gender differences were detected; the prevalence of asthma increased in males from 1995 to 2000, from 14.1 to 17.0%, RR = 1.2 (95% CI 1.0-1.5), but decreased in females 1995 to 2000, from 12.3 to 10.5%, RR = 0.9 (95% CI 0.7-1.1). Furthermore, in children with asthma, a changing trend was found in the external factors that perceived symptoms, from typical allergens towards other, unspecific agents. The prevalence of self-reported atopic eczema/dermatitis syndrome (AEDS) was 13.4, 21.1 and 20.8% in 1985, 1995 and 2000, respectively. The prevalence of self-reported allergic rhinoconjunctivitis was in 16.5, 24.7 and 29.6% 1985, 1995 and 2000, respectively, RR (2000/1995) = 1.2 (95% CI 1.1-1.3).

CONCLUSION

The prevalence of asthma in girls has reached a plateau and even decreased from 1995 to 2000 which is in contrast to the asthma prevalence in boys that tends to continuously increase. The prevalence of AEDS which increased substantially between 1985 and 1995 did not change from 1995 to 2000. However, the prevalence of allergic rhinoconjunctivitis increased steadily from 1985, 1995 to 2000.

No association between serum eosinophil cationic protein and atopic dermatitis or allergic rhinitis in an unselected population of children

BACKGROUND

In order to obtain background references when dealing with serum eosinophil cationic protein (s-ECP) measurements in children with allergic diseases, population-based studies are important. The objectives of our study were to explore the strength of associations between the s-ECP level and atopic dermatitis (AD), allergic rhinitis (AR) and asthma in an unselected northern Norwegian schoolchildren population.

METHODS

s-ECP was sampled from 396 schoolchildren aged 7-12 years from Sør-Varanger community, northern Norway as a part of a population-based study of allergy. In advance, anamnestic information concerning a history of AD, AR and asthma were obtained. The children underwent a clinical investigation, including skin prick tests and peak expiratory flow measurements, where the presence of AD, AR and asthma were evaluated. The associations of these diseases to the s-ECP values were examined in bivariate statistical analysis.

RESULTS

No statistical significant associations were detected in bivariate analysis between s-ECP and AD, AR or asthma: the mean s-ECP in children without self-reported AD/AR/asthma was 4.6 microg/L [95% confidence interval (CI) 4.0-5.2]. The mean s-ECP in children with self-reported AD or AR or asthma was 5.2 microg/L (95% CI 4.1-6.2), 4.6 microg/L (95% CI 3.5-5.7) and 6.4 microg/L (95% CI 4.4-8.3), respectively. The highest mean s-ECP level was measured in children with clinically diagnosed asthma; 7.1 microg/L (95% CI 4.0-10.3). Above the 75-percentile level of s-ECP, only 17.2% of the children had a history of asthma.

CONCLUSIONS

In this unselected children population, the occurrence of AD or AR was not reflected by an increase in the s-ECP level. The s-ECP was increased in children with asthma, but was not statistically significant. Furthermore, the majority of children with high s-ECP values were not asthmatics. We conclude that the associations between s-ECP and allergic diseases are weak in an unselected population of children.

Sulphur dioxide exposure and lung function in a Norwegian and Russian population living close to a nickel smelter

The Norwegian-Russian border area is polluted by sulphur dioxide (SO2) emitted from a Russian nickel smelter in the city of Nikel. We studied the effects of daily variations in SO2 on the lung function levels of people on both sides of the border. A cross-sectional population-based study was performed among adults in Sør-Varanger, Norway (n = 3438) and Nikel, Russia (n = 1613). All subjects were assigned 24 h mean SO2 concentrations for their day of screening and the day before on basis of residency. The SO2-concentrations were compared with the daily recordings of forced expiratory volume in one second expressed as percentage of the predicted value (FEV1% predicted). In Sør-Varanger, no significant associations between SO2 and FEV1% predicted were found. In Nikel, FEV1% predicted was exceeded non-systematically in some of the exposure categories (10-50, 50-90, or > 90 micrograms/m3) compared to the reference exposure group (0-10 micrograms/m3). In conclusion, neither of the study populations suffered from a measurable reduction in lung function when SO2 increased above the reference level.

Asthma and allergy in Russian and Norwegian schoolchildren: results from two questionnaire-based studies in the Kola Peninsula, Russia, and northern Norway

BACKGROUND

Previous studies have shown that the prevalence of asthma and allergy in children is lower in Eastern than Western Europe.

METHODS

We have compared the prevalence of asthma, respiratory symptoms, allergic rhinoconjunctivitis, and atopic dermatitis in schoolchildren aged 7-13 years in a questionnaire-based study conducted in the city of Nikel on the Kola Peninsula, Russia, in 1994 (n = 1143) and another conducted in northern Norway in 1995 (n = 8676).

RESULTS

The prevalence of diagnosed asthma was 5.1% in Russian children and 8.6% in Norwegian children; RR =0.58 (95% CI: 0.44-0.76). The prevalence of all respiratory symptoms was higher in Russian children. The prevalence of allergic rhinoconjunctivitis was 16.9%, in Russian children and 22.1%, in Norwegian children: RR =0.74 (95% CI: 0.65-0.85). The prevalence of atopic dermatitis was 7.4% in Russian children and 19.7% in Norwegian children; RR=0.38 (95% CI: 0.31-0.46).

CONCLUSIONS

We conclude that the prevalence of diagnosed asthma, allergic rhinoconjunctivitis, and atopic dermatitis was higher in Norwegian than Russian schoolchildren. The higher prevalence of respiratory symptoms in Russian children probably reflects a higher prevalence of undiagnosed, nonallergic asthma.

Atopic diseases in Sami and Norse schoolchildren living in northern Norway

Among children in the western world, atopic diseases are a major cause of morbidity. However, several prevalence studies have indicated that the frequency of these diseases displays both geographic and ethnic variations. In 1995, we conducted a questionnaire-based, cross-sectional survey in northern Norway. Atopic diseases among 8676 schoolchildren, aged 7-13 years, including 491 children with Sami ethnicity, were studied. The role of ethnicity (Sami/white Caucasian) was determined by comparing the reported atopic disease rate in each of the respective groups. In the areas under investigation (the cumulative incidence, the point prevalence of asthma and allergic rhinoconjunctivitis and the cumulative incidence of atopic dermatitis), the Sami children scored higher than the white Caucasian Norwegian children. The relative risks (RR) in Sami children were: current asthma RR = 2.01 [95% confidence interval (CI) 1.48-2.73]; current allergic rhinoconjunctivitis RR = 1.51 (95% CI 1.14-1.99); lifetime atopic dermatitis RR = 1.39 (95% CI 1.18-1.63). We thus conclude that there is an association between Sami ethnicity and asthma and allergy among schoolchildren in northern Norway.

[Long-term follow-up of patients after a single-freezing treatment of ectocervical intraepithelial neoplasms]

Fifty-five women aged 21-51 years were treated in 1977 and 1978 with cryocoagulation (single-freezing technique) for cervical intraepithelial neoplasia (CIN I-III). 92% of these patients were followed up 7-8 years after this treatment. The primary success rate i.e. the proportion between the number of women in whom dysplastic changes were not re-encountered within the first 15 months after treatment and the total number of women treated was 94.5%. After the period of observation of 7-8 years, the success rate was 100% for CIN I + II and 79.5% for CIN III.

Plasma 1,25-dihydroxyvitamin D levels in pregnancy and lactation

Plasma concentrations of 1,25-dihydroxyvitamin D (1,25--(OH)2D), serum prolactin and serum parathyroid hormone (PTH) were followed during pregnancy and lactation in 16 women. High 1,25--(OH)2D was demonstrated in human pregnancy and lactation. A causative relationship between 1,25--(OH)2D and prolactin is discussed and a possible explanation of the mechanism of the augmented calcium absorption in human pregnancy and lactation is suggested.