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Biomedical subjects

P Magnus

Publications and source records attributed to P Magnus.

At least 55 records · Page 3Linked to original sources
PubMed1999

Wheezing in school children is not always asthma.

Our objective was to study whether children with reported asthma differed from children with wheeze but without asthma, and from children with neither asthma nor wheeze, regarding lung function, bronchial hyper-responsiveness (BHR) using methacholine inhalation, exercise-induced bronchoconstriction (EIB), and skin prick test (SPT) reactivity. School children (n=2188), enrolled in a survey of asthma, were classified into three mutually exclusive groups by parental report of: asthma, wheeze, and no asthma/no wheeze. A random sample of 80 children in each group was tested (n=240). Among asthmatics, 68% (95% confidence interval (CI), 57-79) had a BHR (measured as PD20 forced expiratory volume in 1 s (FEV1) < or = 8.16 micromol using methacholine) compared to 31% (CI 20-42%) and 30% (CI 19-40%) in the wheeze and no asthma/no wheeze groups. The dose-response slope (DRS) confirmed the PD20 data and distinguished equally between groups. EIB (> or =10% fall in FEV1) was more frequent (40%, CI 29-52%) among asthmatics than among children with wheeze (12%, CI 4-19%) and no asthma/no wheeze (7%, CI 1-13%). The prevalence of at least one positive SPT was twice as high in the asthma group (58%, CI 47-69%) than in the wheeze (27%, CI 16-37%) and the no asthma/no wheeze (25%, CI 15-35%) groups. These results indicate that children with asthma differ from children with wheeze and children with no asthma/no wheeze regarding lung function, BHR, EIB, and SPT reactivity. Children with wheeze are more similar to children with no asthma/no wheeze with respect to these parameters.

Adolescent↗
PubMed1999

Day care attendance, recurrent respiratory tract infections and asthma.

OBJECTIVE: Our objective was to use a causal model for childhood asthma to determine whether the effect of day care attendance on asthma was mediated by recurrent respiratory tract infections. DESIGN: A cross-sectional survey among 1447 children aged 6-16 years in Oslo. Their parents completed written questionnaires. A recursive logit model was used to estimate direct effects in terms of adjusted odds ratios (aOR). RESULTS: Year of birth, number of siblings and length of maternal education were significantly associated with day care attendance. Attendance at day care increased the risk of early infections, aOR = 1.8 (1.3-2.5), and infections were associated with asthma, aOR = 4.9 (3.4-7.3). The crude association between day care and asthma was cOR = 1.5 (1.0-2.2), whereas the estimated direct effect was small and nonsignificant, aOR = 1.2 (0.8-1.9). The results may be influenced by overreporting of infections among parents of children with asthma. CONCLUSIONS: Our results suggest that children who attend day care have an increased risk of asthma with early infections as a mediator of risk.

Absenteeism↗
PubMed1999

Ventilation in homes and bronchial obstruction in young children.

We assessed the role of ventilation rate in homes in the development of bronchial obstruction during the first 2 years of life. We conducted a matched case-control study based on a cohort of 3,754 newborns in Oslo in 1992-93 that was followed for 2 years. The case series comprised 172 children with bronchial obstruction, and the control series was one-to-one matched for date of birth. Ventilation rate and other building characteristics were measured/collected in home visits, and questionnaires were used to obtain additional information. We found that the risk of bronchial obstruction was not directly associated with the ventilation rate in liters per second and per person (ventilation rate quartiles: 6.9, 11.5 and 17.6 l/s,p [liter/second and person]) in the homes (odds ratio; OR 0.98, 95% confidence interval (CI) 0.96-1.01). The odds ratios of bronchial obstruction were higher in the low air change group (air change rate < or =0.5 h(-1)) than in the high air change group owing to exposure to environmental tobacco smoke (low 1.8; 95% CI: 0.35-9.66; high 1.5; 95% CI: 0.74-3.20), dampness problems (low 9.6; 95% CI: 1.05-87.4; high 2.3; 95% CI: 0.83-6.39), and the presence of textile wall paper (low 3.7; 95% CI: 0.62-21.5; high 1.7; 95% CI 0.72-3.94) and plasticizer-containing surfaces (low 12.6; 95% CI: 1.00-159; high 2.6; 95% CI: 1.02-6.58). Our results are consistent with the hypothesis that low ventilation rates strengthen the effects of indoor air pollutants.

Air Pollution, Indoor↗
PubMed1999

Day care centers and respiratory health.

OBJECTIVE: To estimate the effects of the type of day care on respiratory health in preschool children. METHODS: A population-based cross-sectional study of Oslo children born in 1992 was conducted at the end of 1996. A self-administered questionnaire inquired about day care arrangements, children's health, environmental conditions, and family characteristics (n = 3853; response rate, 79%). RESULTS: In logistic regression controlling for confounding, children in day care centers had more often nightly cough (adjusted odds ratio, 1.89; 95% confidence interval, 1.34-2. 67), and blocked or runny nose without common cold (1.55; 1.07-1.61) during the past 12 months compared with children in home care. Poisson regression analysis showed an increased risk of the common cold (incidence rate ratio, 1.21; 1.12-1.30) and otitis media (1.48; 1.22-1.80), and the attributable proportion was 17.4% (95% confidence interval, 10.7-23.1) for the common cold and 32.4% (18. 0-44.4) for otitis media. Early starting age in the day care center increased the risk of developing recurrent otitis media. Also the lifetime risk of doctor-diagnosed asthma was higher in children who started day care center attendance during the first 2 years of life. CONCLUSIONS: Attendance to day care centers increases the risk of upper respiratory symptoms and infections in 3- to 5-year-old children. The starting age seems to be an important determinant of recurrent otitis media as well as asthma. The effect of day care center attendance on asthma is limited to age up to 2 years. This effect is most likely mediated via early respiratory tract infections that are substantially more common in children in day care centers compared with children in home care.

Age Factors↗
PubMed1999

Interior surface materials in the home and the development of bronchial obstruction in young children in Oslo, Norway.

OBJECTIVES: This study assessed the role of polyvinyl chloride (PVC) plastics and textile materials in the home in the development of bronchial obstruction during the first 2 years of life. METHODS: The study was a matched pair case-control study based on a cohort of 3754 newborns in Oslo in 1992 and 1993 who were followed up for 2 years. The case group consisted of 251 children with bronchial obstruction; the control group was matched one-to-one for date of birth. RESULTS: In conditional logistic regression analysis, the risk of bronchial obstruction was related to the presence of PVC flooring (adjusted odds ratio [OR] = 1.89; 95% confidence interval [CI] = 1.14, 3.14) and textile wall materials (adjusted OR = 1.58; 95% CI = 0.98, 2.54). The reference category was wood or parquet flooring and painted walls and ceiling. Further analysis revealed an exposure-response relationship between the assessed amount of PVC and other plasticizer-containing surface materials and the risk of bronchial obstruction. CONCLUSIONS: This study provides new evidence of the role of PVC and textile wall materials in the development of bronchial obstruction in young children.

Bronchial Diseases↗
PubMed1999

Consanguinity and recurrence risk of stillbirth and infant death.

OBJECTIVES: The aim of this study was to estimate the recurrence risk for stillbirth and infant death and compare results for offspring of first-cousin parents with results for offspring of unrelated parents. METHODS: The study population consisted of all single births with a previous sibling born in Norway between 1967 and 1994. Altogether, 629,888 births were to unrelated parents, and 3466 births were to parents who were first cousins. The risk of stillbirth and infant death was estimated for subsequent siblings contingent on parental consanguinity and survival of the previous sibling. RESULTS: For unrelated parents, the risk of early death (stillbirth plus infant death) for the subsequent sibling was 17 of 1000 if the previous child survived and 67 of 1000 if the previous child died before 1 year of age. For parents who were first cousins, the risk of early death for the subsequent sibling was 29 of 1000 if the previous child survived and 116 of 1000 if the previous child died. CONCLUSIONS: The risk of recurrence of stillbirth and infant death is higher for offspring of first-cousin parents compared with offspring of unrelated parents.

Adult↗
PubMed1999

Rapid changes in the prevalence of obesity and known diabetes in an adult Norwegian population. The Nord-Trøndelag Health Surveys: 1984-1986 and 1995-1997.

OBJECTIVE: To determine whether changes in mean BMI and the prevalence of obesity in a total adult population during a short (11-year) period were associated with changes in the prevalence of diabetes. RESEARCH DESIGN AND METHODS: This study involved cross-sectional surveys of all inhabitants aged > or = 20 years of the county of Nord-Trøndelag from 1984 to 1986 (n = 85,100) and from 1995 to 1997 (n = 92,434). Attendance rates were 88.1 and 71.3%, respectively, and 90.0% in an additional survey of people aged 13-19 years from 1995 to 1997 (n = 9,593). Main outcome measures were age-specific mean BMI for the diabetic and nondiabetic subgroups and the prevalence of obesity and diabetes. For comparison, mean BMIs from 18 of 19 Norwegian counties for the group aged 40-42 years were examined. RESULTS: Mean BMI increased from 27.2 to 29.0 kg/m2 in the diabetic population and from 25.1 to 26.3 kg/m2 in the nondiabetic population. The BMI distribution curve shifted to the right, but homogeneity was also reduced. A comparison with other Norwegian counties indicated that this increase occurred during the last 6 years between the surveys. The prevalence of obesity (BMI > or = 30 kg/m2) increased from 7.5 to 14% in nondiabetic men and from 13 to 18% in nondiabetic women. The increase was particularly great in men aged < 60 years and in women aged < 50 years. The overall prevalence of known diabetes increased between the two surveys (from 2.9 to 3.2%) but only in men. The largest increase was observed in the corresponding younger sex and age-groups. CONCLUSIONS: A substantial increase in mean BMI and the prevalence of obesity occurred in the younger age-groups at the same time as an increase in the prevalence of diabetes. A greater increase in diabetes prevalence in this ethnically stable Western European population may follow if effective primary preventive strategies are not undertaken.

Adolescent↗
PubMed1999

Water chlorination and birth defects.

Chlorination of drinking water that contains organic compounds leads to the formation of by-products, some of which have been shown to have mutagenic or carcinogenic effects. As yet, too little is known about the possible teratogenic effects on the human fetus. We linked the Norwegian waterwork registry, containing 1994 data on chlorination practice and color (an indicator for natural organic matter), with the Medical Birth Registry for 1993-1995. The proportion of the population exposed to chlorination and a weighted mean color number in drinking water was computed for each municipality. Among 141,077 births, 2,608 (1.8%) had birth defects. In a comparison between exposed (high color; chlorination) and reference groups (low color; no chlorination), the adjusted odds ratio was 1.14 (0.99-1.31) for any malformation, 1.26 (0.61-2.62) for neural tube defects, and 1.99 (1.10-3.57) for urinary tract defects. This study provides further evidence of the role of chlorination of humic water as a potential cause of birth defects, in a country with relatively low levels of chlorination byproducts.

Abnormalities, Drug-Induced↗
PubMed1998

Birth weight and mortality in childhood in Norway.

In order to estimate the association between intrauterine growth and childhood survival, data on birth weight and gestational age from the Norwegian Birth Registry, for all children who survived the first year of life and who were born during the period 1967-1989 were linked to the National Cause of Death Registry for the period 1968-1991. Deaths were categorized into five cause of death groups: malformations, cancer, infections, accidents, and other causes. The adjusted relative risk of death from all causes at ages 1-5 years was 2.18 (95% confidence interval (CI) 1.85-2.56) for children with birth weight <2,500 g as opposed to children with birth weight > or = 2,500 g. For ages 6-10 years, the corresponding adjusted relative risk (95% CI) was 1.83 (1.35-2.48), and for ages 11-15 years, it was 1.35 (0.91-1.99). Death from infections, accidents, and other causes showed a reversed J-shaped association with birth weight, while malformations showed a log-linear decrease in mortality with increasing birth weight. For cancer deaths, low birth weight showed an opposite association. The association between birth weight and childhood mortality is complex, and cause-specific analyses are necessary to understand the connection between intrauterine influences and later mortality.

Accidents↗
PubMed1998

Influence of consanguinity and maternal education on risk of stillbirth and infant death in Norway, 1967-1993.

To analyze the influence of consanguinity and maternal education on stillbirth and infant death for children born in Norway between 1967 and 1993, the authors studied 7,274 children of ethnic Pakistani origin and 1,431,055 children of Norwegian ethnic origin. Of these children, 31.0% of the Pakistani children and 0.1% of the Norwegian children had parents who were first cousins. Consanguinity increased the relative risk of stillbirth (odds ratio (OR) = 1.3, 95% confidence interval (CI) 1.0-1.6) and infant death (OR = 2.4, 95% CI 2.0-3.0), after adjustment for maternal education, maternal age, parity, and year of birth. In 1985-1993, 29% (95% CI 13-45) of stillbirths and infant deaths among the Pakistani group were attributable to consanguinity. In the Norwegian group, 17% (95% CI 13-21) of the deaths were attributable to factors associated with low maternal education, while in the Pakistani group, the corresponding estimate was nonsignificant. The risks of stillbirth and infant death were similar for children with non-consanguineous parents in both populations. This is an important observation considering the differences in socioeconomic status between the two groups. The authors conclude that consanguinity influenced stillbirth and infant death independent of maternal education, and that a large proportion of deaths could be attributed to consanguinity in the Pakistani group due to high frequencies of consanguinity.

Consanguinity↗
PubMed1998

An increased risk of cervical intra-epithelial neoplasia grade II-III among human papillomavirus positive patients with the HLA-DQA1*0102-DQB1*0602 haplotype: a population-based case-control study of Norwegian women.

Several recent studies have reported different associations between HLA specificities and human papillomavirus (HPV)-associated disease of the cervix. We report the distribution of DQA1 and DQB1 genes and HPV infection in a population-based case-control study including 92 patients with histologically verified cervical intraepithelial neoplasia grade II-III (CIN II-III) (thus including moderate and severe dysplasia and carcinoma in situ) and 225 control subjects. We found an overrepresentation of the DQA1*0102-DQB1*0602 haplotype among HPV-positive cases compared with controls. The association was even stronger when comparing HPV-16-positive cases with HPV-16-positive controls. In addition, among HPV-16-positive individuals, we observed a decreased frequency of DQA1*0102-DQB1*0604 in cases compared with controls. We were not able to detect any association between CIN II-III and DQB1*03. Compared with previous findings in cervical cancer, our data indicate that carrying the DQA1*0102-DQB1*0602 haplotype gives an increased risk of developing CIN when infected with HPV-16, without influencing progression to cancer.

Adult↗
PubMed1998

[Risk assessment in preventive medicine].

The aim of this article is to present and discuss the value of risk analysis in preventive medicine. Risk analysis consists of three major areas; risk assessment, risk management and risk communication. Risk analysis is illustrated here by two examples: exposure to radon and the risk of lung cancer, and infection with toxoplasma gondii in pregnancy and adverse pregnancy outcome. The analyses highlight the complementary elements of scientific judgement and political valuation. The barriers against implementation of preventive measures are many. Adequate risk assessment and consequence analysis based on empirical studies, together with risk communication are important for implementing the correct measures. We suggest that risk analysis should be used more often in medicine as a tool for systematic evaluation of the need and usefulness of preventive measures.

Female↗
PubMed1998

Increasing risk of asthma without other atopic diseases in school children: a repeated cross-sectional study after 13 years.

Some children develop asthma and other atopic diseases, others asthma without atopic diseases. To better understand secular trends, we estimated the relative increase in asthma in children with (atopy related asthma) and without (non-atopy related asthma) other atopic diseases (eczema or hay fever) in two samples of school children born, 1965-1975 (n = 1674) and 1978-1988 (n = 2188). By analysing the samples as historical cohorts, age-specific prevalence rates were estimated and incidence rates were calculated (number of new cases by 1000 person years under risk). Cox regression was used to estimate the relative risk (RR) of asthma by year of birth. The point prevalence of asthma was 1.9% (95% CI: 1.4-2.4) in the 1965-1975 cohort and 4.6% (95% CI: 3.8-5.4) in the 1978-1988 cohort for three-year old children, and remained fairly constant throughout childhood. The age-specific prevalence of non-atopy related asthma increased relatively more from 1965-1975 to 1978-1988 compared to atopy related asthma. The age-specific incidence rates of asthma showed that the RRs comparing the two cohorts tended at all ages to be highest for non-atopy related asthma. The relative risks of non-atopy related asthma by gender and birth cohort, showed that the effect of cohort was higher for non-atopy related asthma, aRR: 4.0 (95 % CI: 2.5-6.5), than for atopy-related asthma aRR: 2.0 (95% CI: 1.3-3.2). Children without other atopic diseases have a higher relative risk of being diagnosed with asthma than children with other atopic diseases across all ages comparing two samples of school children born 1965-1975 and 1978-1988.

Adolescent↗
PubMed1998

Neck/shoulder and low-back disorders in the forestry industry: relationship to work tasks and perceived psychosocial job stress.

In a national cross-sectional study, the prevalence of neck/shoulder and low-back disorders and their relationship to work tasks and perceived psychosocial job stress was studied among forestry employees. The data were collected by occupational health service staff using Karasek's demand/control questionnaire for the psychosocial measures and the Standardized Nordic questionnaire for the analysis of musculoskeletal disorders. Based on data about past and present work tasks, the study population was classified into three groups: 645 manual workers, 66 machine operators and 124 administrative workers. Low-back disorders were more common among the manual workers than among the administrative workers [odds ratio (OR) = 1.98]. For the machine operators and manual workers, an increasing level of psychological demands was significantly associated with an increased prevalence of low-back disorders. The prevalence of neck/shoulder disorders was significantly higher among the machine operators (OR = 3.37) and manual workers (OR = 2.34) than among the administrative workers. An increasing level of psychological demands combined with a decreasing level of intellectual discretion was associated with an increased prevalence of neck/shoulder disorders. Authority over decisions was not associated with musculoskeletal disorders. In conclusion, musculoskeletal disorders were associated with both physical and psychosocial work factors. The modest strength of the associations between each individual independent variable and the outcome measure shows, however, that a substantial reduction in the prevalence of musculoskeletal disorders may be difficult to achieve. Nevertheless, the study clearly suggests that in the forestry industry attention should be paid to psychosocial work factors in future organizational changes and preventive programmes.

Adult↗
PubMed1998

Is there a consequence for fetal growth of having an unlike-sexed cohabitant in utero?

BACKGROUND: There is evidence to suggest a masculinizing effect on female intrauterine development in unlike-sexed twins. The purpose of the present report was to examine the possible effects of male presence on fetal growth in females by comparing mean birthweights in members from dizygotic unlike-sexed (DZU) pairs with those from dizygotic like-sexed (DZL) pairs. METHODS: The sample consisted of 1087 DZU and 1089 DZL twin pairs from the New Norwegian Twin Panel, which was established by identifying all twin births from 1967 to 1974 through the population-based Medical Birth Registry. RESULTS: The mean birthweight of females from DZU pairs was 2684+/-15 g (+/-SEM), as opposed to 2647+/-19 g in females from DZL pairs (P = 0.06). For males, the mean birthweight was 2812+/-16 g in DZU pairs and 2805+/-20 g in DZL pairs (P= 0.78). CONCLUSION: We found a tendency for the birthweight in females to be influenced by the presence of a male co-twin. This observation may have a biological significance and should lead to a close follow-up of DZU and DZL females with respect to hormone-sensitive disorders and reproductive ability.

Birth Weight↗
PubMed1998

Exposure to nitrogen dioxide and the occurrence of bronchial obstruction in children below 2 years.

BACKGROUND: The objective of the investigation was to test the hypothesis that exposure to nitrogen dioxide (NO2) has a causal influence on the occurrence of bronchial obstruction in children below 2 years of age. METHODS: A nested case-control study with 153 one-to-one matched pairs was conducted within a cohort of 3754 children born in Oslo in 1992/93. Cases were children who developed > or = 2 episodes of bronchial obstruction or one episode lasting >4 weeks. Controls were matched for date of birth. Exposure measurements were performed in the same 14-day period within matched pairs. The NO2 exposure was measured with personal samplers carried close to each child and by stationary samplers outdoors and indoors. RESULTS: Few children (4.6%) were exposed to levels of NO2 > or = 30 microg/m3 (average concentration during a 14-day period). In the 153 matched pairs, the mean level of NO2 was 15.65 microg/m3 (+/-0.60, SE) among cases and 15.37 (+/-0.54) among controls (paired t = 0.38, P = 0.71). CONCLUSIONS: The results suggest that NO2 exposure at levels observed in this study has no detectable effect on the risk of developing bronchial obstruction in children below 2 years of age.

Air Pollution, Indoor↗