Grete Botten

The prevalence of allergy to egg: a population-based study in young children.

Background: The aim of the present study was to estimate the prevalence of adverse reactions to egg, as population‐based prevalence estimates based on objective diagnostic procedures are lacking.

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.

Breastfeeding, maternal smoking and lower respiratory tract infections

The objective of the study was to assess the relationship between breastfeeding and lower respiratory tract infections (LRTIs) during the first year of life, with special reference to maternal smoking. A cohort of 3,754 children born in 1992-1993 in the City of Oslo, Norway was recruited and data were collected at birth, 6 and 12 months of age. Complete information was obtained from 3,238 children (follow-up rate 86%). The main outcome was an episode of a LRTI, such as pneumonia, bronchitis or bronchiolitis, based on a self-administered questionnaire addressed to parents when the child was 6 and 12 months old. The outcome was specified as physician-diagnosed. In logistic regression analysis adjusting for confounding, maternal smoking increased the risk of LRTIs in children breastfed for 0-6 months (odds ratio (AOR) 1.7; 95% confidence interval (95% CI) 1.2-2.4), but not essentially when the child was breastfed for more than 6 months (AOR 1.1; 95% CI 0.7-1.6). Short-term breastfeeding (0-6 months) and no maternal smoking was related to an adjusted AOR of LRTIs of 1.3 (95% CI 1.0-1.7), and short-term breastfeeding combined with maternal smoking was related to an adjusted AOR of 2.2 (95% CI 1.6-3.1), as compared with long-term breastfeeding and no maternal smoking. The present study indicates a protective effect of long-term breastfeeding on the risk of lower respiratory tract infection during the first year of life. The results suggest that the protective effect is strongest in children exposed to environmental tobacco smoke.

Prevalence of parentally perceived adverse reactions to food in young children

A substantial number of parents perceive that their children have adverse reactions to food, but it is well documented that objective assessments agree with only one‐quarter to one‐half of parentally reported reactions. In order to prevent wrong diagnoses and curtail unnecessary or inadequate diets, primary health care providers need to deal with the parental perception of adverse reactions to food. A description of the prevalence and pattern of parentally perceived adverse reactions to food in children is needed to meet this challenge. The aim of the present study was to estimate the prevalence, incidence and cumulative incidences of parentally perceived adverse reactions to food in children younger than 2 years of age, and to study the duration of the reactions. A population‐based cohort of 3623 children born in Norway was followed from birth until the age of two. At 6‐month intervals, the parents completed questionnaires regarding the occurrence and type of any reaction to food. Information was available on the outcome measure at all age points for 77.4% of the families and these were used in the analyses; 3.8% of the cohort were entirely lost to follow‐up. The cumulative incidence of adverse reactions to food was 35% by age two. Fruits, milk and vegetables accounted for nearly two‐thirds of all reported reactions. Milk was the single food item most commonly incriminated, the cumulative incidence being 11.6%. The cumulative incidences of reported reactions to fruits and vegetables were 20.4% and 7.3%, respectively, with citrus fruits, strawberry and tomatoes as the most common food items in these groups. The cumulative incidences were less for food reactions associated with eggs (4.4%), fish (3%), nuts (2.1%) and cereals (1.4%). The duration of the reactions was short – approximately two‐thirds of the reactions were not reported again 6 months later. However, the probability of remission depended on the food item concerned, the age at onset of reactions, and whether the reaction had been reported previously or not. Adverse reactions to food are reported by the parents of one‐third of children in Norway before the age of two. The most striking feature of this study is the short duration of the food reactions, as approximately two‐thirds of the reactions are not reported again 6 months later. Nevertheless, the high frequency of reactions attributable to milk is of concern. Milk is an important part of the Norwegian diet for children, and if removed from the diet its nutritional value is not easily replaced. Further studies are needed to assess the degree to which parents alter the diet of their children based upon perceived reactions to food.

The prevalence of CMA/CMPI in young children: the validity of parentally perceived reactions in a population-based study

Background: The present study aimed to estimate the prevalence of adverse reactions to milk, as population‐based prevalence estimates based on objective diagnostic procedures are rare.

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.

Female medical leadership : cross sectional study

Objective: To assess the relation between male and female medical leadership. Design: Cross sectional study on predictive factors for female medical leadership with data on sex, age, specialty, and occupational status of Norwegian physicians. Setting: Oslo,Norway. Subjects: 13844 non-retired Norwegian physicians. Main outcome measure: Medical leaders, defined as physicians holding a leading position in hospital medicine, public health, aacademic medicine, or private health care. Results: 14.6% (95% confidence interval 14.0% to 15.4%) of the men were leaders compared with 5.1% (4.4% to 5.9%) of the women. Adjusted for age men had a higher estimated probability of leadership in all categories of age and job, the highest being in academic medicine with 0.57(0.42to 0.72) for men aged over 54years compared with 0.39(0.21to 0.63) for women in the same category. Among female hospital physicians there was a positive relation between the proportion of women in their specialty and the probability of leadership. Conclusion: Women do not reach senior positions as easily as men. Medical specialties with high proportions of women have more female leaders.

The role of passive smoking in the development of bronchial obstruction during the first 2 years of life

We assessed the effect of exposure to environmental tobacco smoke on the risk of developing bronchial obstruction in a 2‐year cohort study of 3,754 children born in Oslo, Norway, during a period of 15 months in 1992–1993. We collected questionnaire information on the childs health and environmental exposures at birth and when the child was age 6 months (follow up rate = 95%), 12 months (92%), 18 months (92%), and 24 months (81%). The outcome of interest was defined as two or more episodes of bronchial obstruction or one obstruction lasting more than 1 month, and it was verified by a specialist group evaluating data from questionnaires, clinical examinations, and health records. The risk of bronchial obstruction was increased in children exposed to environmental tobacco smoke (cumulative incidence = 0.109) compared with unexposed children (0.071), with an adjusted odds ratio of 1.6 [95% confidence interval (CI) = 1.3–2.1]. The effect was seen for maternal smoking alone (odds ratio = 1.6; 95% CI = 1.0–2.6), paternal smoking alone (odds ratio = 1.5; 95% CI = 1.1–2.2), and both parents smoking (odds ratio = 1.5; 95% CI = 1.0–2.2). There was no clear exposure‐response pattern. The findings indicate that exposure to environmental tobacco smoke such as is experienced in Norwegian housing increases the risk of developing bronchial obstruction during the first 2 years of life.

Prevalence and persistence of stomach ache and headache among children. Follow-up of a cohort of Norwegian children from 4 to 10 years of age

Results from a prospective cohort of 136 children, from 4 to 10 years of age, indicated that stomach ache was almost as prevalent among preschool children as children of school age. Headache was almost absent among 4‐year‐olds but prevalent at 10 years of age. Generally, early pain complaints were persistent. The co‐occurrence of stomach ache and headache increased from 4% of children at 4 years of age to 20% when they reached 10 years of age.

Fetal exposure to tobacco smoke products: A comparison between self-reported maternal smoking and concentrations of cotinine and thiocyanate in cord serum

Background: The objective of the study was to assess the relationship between maternal smoking habits and biomarkers of tobacco smoke measured in cord serum.