Low agreement between Swedish national registers and parental questionnaires on allergic rhinitis.

BACKGROUND: Allergic rhinitis (AR) has been well documented using questionnaire-based studies. Here, we examine the agreement between parental-reported data during childhood with the emphasis on 12-year-olds and data from two national Swedish registers to determine whether register data on AR can supplement or replace questionnaire data. METHODS: Data were collected from a prospective, longitudinal cohort study of children born in western Sweden in 2003. Parental questionnaires were filled out at 6 months and one, four, eight, and 12 years of age. A total of 3634 children were linked to the Swedish Prescribed Drug Register (SPDR) and the National Patient Register (NPR) using personal identity numbers. The agreement between the register and questionnaire data was estimated using Cohen's kappa with 95% confidence intervals. RESULTS: According to the SPDR, 9.9% (n = 360/3634) of the children were dispensed specific AR medication at 11-13 years of age compared with the 12 years questionnaire where 23% reported AR medication use during the last 12 months. The overall agreement between questionnaire and SPDR data on AR medication was slight (kappa 0.05). At 11-12 years, 1.8% (n = 65/3634) of the children received an outpatient AR diagnosis in the NPR, while 10% reported doctor-diagnosed AR in the questionnaire. The overall agreement between questionnaire and NPR data on AR diagnosis was slight (kappa 0.16). CONCLUSIONS: There was poor agreement between questionnaire and register data regarding AR and dispensed medication. Explanations could include over-the-counter drugs and diagnosis in primary care, which are not included in the registers.

Asthma increased in young adults from 2008-2016 despite stable allergic rhinitis and reduced smoking.

BACKGROUND: Studies have produced inconsistent results on prevalence trends in asthma and allergic rhinitis (AR). We surveyed young adults about asthma in 2008 and 2016 and examined the impact of gender, AR and smoking. METHODS: Thirty-thousand randomly selected subjects aged 16-75 years in Western Sweden received postal questionnaires in 2008 and 50,000 in 2016. This study is based on responders aged 16-25 years, 2,143 in 2008 and 2,484 in 2016. RESULTS: From 2008-2016 current asthma increased from 9.3% to 11.5% (p = 0.014) and was significant in males without AR (aOR 1.83, 95% CI 1.09-3.07) and male smokers (aOR 3.02, 95% CI 1.12-8.13). In both years the risk of current asthma was reduced by growing up on a farm (aOR 0.26, 95% CI 0.81-0.84 and aOR 0.47, 95% CI 0.23-0.996), independent of a family history of asthma or allergy. AR did not differ significantly from 2008-2016 (22.5% vs 24.4%, p = 0.144). Current smoking decreased from 20.3% to 15.2% (p<0.001), especially in females (23.5% to 16.2%, p<0.001). Female smokers started smoking later and smoked fewer cigarettes in 2016 than 2008. In 2016, 4.8% of the cohort reported using electronic cigarettes. Of those, 60.7% also smoked tobacco and more than two-thirds who used both (67.2%) were heavy smokers. CONCLUSION: Current asthma increased in respondents aged 16-25 from 2008-2016, mainly among males without AR and male smokers. Current AR levelled off in this young population, while current smoking decreased among females.

Parental questionnaires provided reliable data on childhood asthma compared with national registers.

BACKGROUND: Much of our knowledge of childhood asthma comes from questionnaire-based studies. Our main aim was to assess the agreement between parental-reported data at 12 years of age and data from two national Swedish registers. METHODS: Data were obtained from the prospective, longitudinal, population-based Children of Western Sweden cohort, which focused on children born in 2003. The parents answered questionnaires at six months and one, four, eight and 12 years of age. Personal identity numbers linked 3634 children to the Swedish Prescribed Drug Register (SPDR) and the National Patient Register (NPR). RESULTS: At 12 years of age, there was substantial overall agreement between the asthma medication reported by the parents in the questionnaire and the SPDR for any asthma medication (94.8%, kappa 0.71) and maintenance treatment (95.3%, kappa 0.68). In contrast, the agreement between the outpatient asthma diagnoses in the NPR and the questionnaire-based asthma was 30.5% and it was 32.8% between the NPR and the dispensed asthma medication in the SPDR. Hospitalization was rare for obstructive diseases after early childhood, and 38.2% of the 12-year-old children only received a short-acting beta agonist, with no maintenance treatment. CONCLUSION: There was good agreement between the questionnaire-based data on asthma medication and the national drug register, but the National Patient Register provided incomplete information on asthma diagnoses, probably because it did not include primary care diagnoses. The results show that well-constructed parental questionnaires can provide reliable data on childhood asthma.

Higher parental education was associated with better asthma control.

AIM: Inhaled corticosteroids have resulted in the improved control of asthma and a reduced need for hospitalisation. This study aimed to examine the prevalence of uncontrolled asthma and factors that affect asthma control. METHODS: The data came from a longitudinal cohort study of children. The parents answered questionnaires from age 6 months to 12 years. The response rate at age 12 years was 76% (3637/4777) and doctor-diagnosed asthma was reported in 6.4% (n = 233). Asthma control was examined with the Asthma Control Test (ACT), where scores below 20 denote uncontrolled asthma. RESULTS: Of the children with asthma at age 12 years, 15% had an ACT value below 20, that is uncontrolled asthma. Independent risk factors for uncontrolled asthma were wheeze triggered by exercise (adjusted OR, aOR 5.6; 1.9-16.6), cat at home (aOR 3.5; 1.2-10.0) and current doctor-diagnosed rhinitis (aOR 2.8; 95% CI 1.1-7.0). A higher education in the parents reduced the risk of uncontrolled asthma (aOR 0.3; 95% CI 0.1-0.8). Only six children (i.e. 2.6%) reported hospitalisation due to asthma during the last year. CONCLUSION: Of the children with asthma, 15% had uncontrolled asthma. Higher education in the parents was associated with better asthma control in the children.

Antibiotics in the first week of life were associated with atopic asthma at 12 years of age.

AIM: This study explored the prevalence of atopic and nonatopic asthma in 12-year-old children and whether they were associated with different risk factors. In particular, we wanted to analyse whether receiving antibiotics during the first week of life was associated with asthma at that age. METHODS: Data were obtained from a longitudinal cohort study of 5654 Swedish children born in 2003. The parents answered questionnaires from the age of six months until 12 years. The response rate at 12 years was 3637/4777 (76%). RESULTS: At 12 years, 6.4% reported current doctor-diagnosed asthma. Treatment with antibiotics during the first week of life was associated with an increased risk of atopic asthma, with an adjusted odds ratio of 2.2 and 95% confidence interval of 1.2-4.2. Being born small for gestational age was associated with an increased risk of nonatopic asthma, with an adjusted odds ratio of 3.8 and 95% confidence interval of 1.1-13.7. Asthma that only occurred with colds was reported by 28%. CONCLUSION: Antibiotic treatment during the first week of life was associated with an increased risk of atopic asthma at 12 years, suggesting an immune-mediated effect. Being born small for gestational age increased the risk of nonatopic asthma.

Eating fish and farm life reduce allergic rhinitis at the age of twelve.

BACKGROUND: The prevalence of allergic rhinitis has increased, but the cause of this rise is partly unknown. Our aim was to analyse the prevalence, risk factors, and protective factors for allergic rhinitis in 12-year-old Swedish children. METHODS: Data were collected from a prospective, longitudinal cohort study of children born in western Sweden in 2003. The parents answered questionnaires when the children were 6 months to 12 years. The response rate at 12 years was 76% (3637/4777) of the questionnaires distributed. RESULTS: At the age of 12, 22% of children had allergic rhinitis and 57% were boys. Mean age at onset was 7.8 years, and 55% reported their first symptoms after 8 years. The most common trigger factors were pollen (85%), furry animals (34%), and house dust mites (17%). A multivariate analysis showed that the adjusted odds ratios and 95% confidence intervals for the independent risk factors for allergic rhinitis at 12 were as follows: parental allergic rhinitis (2.32, 1.94-2.77), doctor-diagnosed food allergy in the first year (1.75, 1.21-2.52), eczema in the first year (1.61, 1.31-1.97), and male gender (1.25, 1.06-1.47). Eating fish once a month or more at age of 12 months reduced the risk of allergic rhinitis at 12 years of age (0.70, 0.50-0.98) as did living on a farm with farm animals at 4 years (0.51, 0.32-0.84). Continuous farm living from age 4 to 12 seemed to drive the association. CONCLUSIONS: Allergic rhinitis affected > 20% of 12-year-olds, but was lower in children who ate fish at 12 months or grew up on a farm with farm animals.