No abstract

There is evidence that the origin of obstructive lung disease may be traced back to foetal life. The associations between birth characteristics and asthma symptoms were studied in a random population sample of young Norwegian adults. Respiratory symptoms were recorded in a population-based questionnaire survey. The records of all subjects aged 20-24 yrs were linked with the Medical Birth Registry of Norway. Of 868 subjects born in Norway, there were 690 (79%) responders. The associations between asthma symptoms and birth characteristics were analysed by logistic regression, adjusted for possible confounding factors. Asthma symptoms in young adults were inversely associated with birth weight (odds ratio (OR)wheeze=0.82; 95% confidence interval (CI)=0.69-0.96x500 g increase in birth weight(-1))), and after adjustment for gestational age, birth length, parity and maternal age (ORwheeze=0.69; 95% CI=0.50-0.95x500 g increase in birth weight(-1)). The association did not vary according to adult smoking habits or atopic status and remained when premature and low weight births were excluded (ORwheeze=0.73; 95% CI=0.60-0.90x500 g increase in birth weight(-1)). The association was consistent for all asthma symptoms. Adjusted for birth weight, asthma symptoms were further associated with low gestational age, high birth length and low maternal age. In a random sample of young adults, asthma symptoms were strongly associated with low birth weight, an association driven by the full-term births within the normal birth weight range. The findings show that the risk for adult asthma is partly established early in life and suggest that poor intrauterine growth is involved in the aetiology of asthma.

Aim-To establish whether smoking is an independent risk factor for sudden infant death syndrome (SIDS), if the eVect is mainly due to prenatal or postnatal smoking, and the eVect of smoking cessation. Methods-The analyses were based on data from the Nordic epidemiological SIDS study, a case-control study with 244 cases and 869 controls. Odds ratios were computed by conditional logistic regression analysis. Results-Smoking emerged as an independent risk factor for SIDS, and the eVect was mainly mediated through maternal smoking in pregnancy (crude odds ratio 4.0 (95% confidence interval 2.9 to 5.6)). Maternal smoking showed a marked dose-response relation. There was no eVect of paternal smoking if the mother did not smoke. Stopping or even reducing smoking was beneficial. SIDS cases exposed to tobacco smoke were breast fed for a shorter time than non-exposed cases, and feeding diYculties were also more common. Conclusions-Smoking is an independent risk factor for SIDS and is mainly mediated through maternal smoking during pregnancy. Stopping smoking or smoking less may be beneficial in reducing the risk of SIDS. (Arch Dis Child 1998;78:329-334)

A prospective case-control study of sudden infant death syndrome (SIDS) in Norway, Denmark and Sweden between September 1, 1992 and August 31, 1995 comprised 244 cases and 869 matched controls. After the introduction of risk-intervention campaigns, the SIDS incidence decreased from 2.3/1000 live births in Norway, 1.6 in Denmark and 1.0 in Sweden to 0.6/1000 or fewer in all the Scandinavian countries in 1995. The decrease paralleled a decline in the prone sleeping position and there was an accompanying parallel fall in total postneonatal mortality in all three countries. Thus, the risk-reducing campaigns for SIDS have been successful not only in Norway and Denmark, starting from relatively high incidences, but also in Sweden, starting from a low incidence. During the study period, a gradual increase was observed for the effects of prone sleeping, smoking and bottle-feeding as risk factors for SIDS.