Mikael Hasselgren

The association between asthma and allergic symptoms in children and phthalates in house dust : a nested case-control study

Global phthalate ester production has increased from very low levels at the end of World War II to approximately 3.5 million metric tons/year. The aim of the present study was to investigate potential associations between persistent allergic symptoms in children, which have increased markedly in developed countries over the past three decades, and the concentration of phthalates in dust collected from their homes. This investigation is a case–control study nested within a cohort of 10,852 children. From the cohort, we selected 198 cases with persistent allergic symptoms and 202 controls without allergic symptoms. A clinical and a technical team investigated each child and her or his environment. We found higher median concentrations of butyl benzyl phthalate (BBzP) in dust among cases than among controls (0.15 vs. 0.12 mg/g dust). Analyzing the case group by symptoms showed that BBzP was associated with rhinitis (p = 0.001) and eczema (p = 0.001), whereas di(2-ethylhexyl) phthalate (DEHP) was associated with asthma (p = 0.022). Furthermore, dose–response relationships for these associations are supported by trend analyses. This study shows that phthalates, within the range of what is normally found in indoor environments, are associated with allergic symptoms in children. We believe that the different associations of symptoms for the three major phthalates—BBzP, DEHP, and di-n-butyl phthalate—can be explained by a combination of chemical physical properties and toxicologic potential. Given the phthalate exposures of children worldwide, the results from this study of Swedish children have global implications.

Common household chemicals and the allergy risks in pre-school age children.

Background The risk of indoor exposure to volatile organic compounds (VOCs) on allergic airway diseases in children remains unknown. Objective We examined the residential concentrations of VOCs, emitted from building materials, paints, furniture, and other lifestyle practices and the risks of multiple allergic diseases as well as the IgE-sensitization in pre-school age children in Sweden. Methods In a case-control investigation (198 case children with asthma and allergy and 202 healthy controls), air samples were collected in the room where the child slept. The air samples were analyzed for the levels of eight classes of VOCs. Results A natural-log unit of summed propylene glycol and glycol ethers (PGEs) in bedroom air (equal to interquartile range, or 3.43 – 15.65 µg/m3) was associated with 1.5-fold greater likelihood of being a case (95% CI, 1.1 – 2.1), 1.5-fold greater likelihood of asthma (95% CI, 1.0 – 2.3), 2.8-fold greater likelihood of rhinitis (95% CI, 1.6 – 4.7), and 1.6-fold greater likelihood of eczema (95% CI, 1.1 – 2.3), accounting for gender, secondhand smoke, allergies in both parents, wet cleaning with chemical agents, construction period of the building, limonene, cat and dog allergens, butyl benzyl phthalate (BBzP), and di(2-ethylhexyl)phthalate (DEHP). When the analysis was restricted to the cases, the same unit concentration was associated with 1.8-fold greater likelihood of IgE-sensitization (95% CI, 1.1 – 2.8) compared to the non-IgE sensitized cases. No similar associations were found for the other classes of VOCs. Conclusion We propose a novel hypothesis that PGEs in indoor air exacerbate and/or induce the multiple allergic symptoms, asthma, rhinitis and eczema, as well as IgE sensitization respectively.

Eczema in early childhood is strongly associated with the development of asthma and rhinitis in a prospective cohort

BackgroundThis study aimed to estimate the association between eczema in early childhood and the onset of asthma and rhinitis later in life in children.MethodsA total of 3,124 children aged 1–2 years were included in the Dampness in Building and Health (DBH) study in the year 2000, and followed up 5 years later by a parental questionnaire based on an International Study of Asthma and Allergies in Childhood protocol. The association between eczema in early childhood and the incidence of asthma and rhinitis later in life was estimated by univariable and multivariable logistic regression modelling.ResultsThe prevalence of eczema in children aged 1–2 years was 17.6% at baseline. Children with eczema had a 3-fold increased odds of developing asthma (adjusted odds ratio [aOR], 3.07; 95% confidence interval (CI) 1.79–5.27), and a nearly 3-fold increased odds of developing rhinitis (aOR, 2.63; 1.85–3.73) at follow-up compared with children without eczema, adjusted for age, sex, parental allergic disease, parental smoking, length of breastfeeding, site of living, polyvinylchloride flooring material, and concomitant allergic disease. When eczema was divided into subgroups, moderate to severe eczema (aOR, 3.56; 1.62–7.83 and aOR, 3.87; 2.37–6.33, respectively), early onset of eczema (aOR, 3.44; 1.94–6.09 and aOR, 4.05; 2.82–5.81; respectively), and persistence of eczema (aOR, 5.16; 2.62–10.18 and aOR, 4.00; 2.53–6.22, respectively) further increased the odds of developing asthma and rhinitis. Further independent risk factors increasing the odds of developing asthma were a parental history of allergic disease (aOR, 1.83; 1.29–2.60) and a period of breast feeding shorter than 6 months (aOR, 1.57; 1.03–2.39). The incidence of rhinitis was increased for parental history of allergic disease (aOR, 2.00; 1.59–2.51) and polyvinylchloride flooring (aOR, 1.60; 1.02–2.51).ConclusionEczema in infancy is associated with development of asthma and rhinitis during the following 5-year period, and eczema is one of the strongest risk factors. Early identification is valuable for prediction of the atopic march.

Estimated prevalences of respiratory symptoms, asthma and chronic obstructive pulmonary disease related to detection rate in primary health care

OBJECTIVE To assess the prevalence of respiratory symptoms, asthma and chronic obstructive pulmonary disease (COPD), and to relate it to an estimated detection rate in primary health care. DESIGN A two-staged study with a cross-sectional survey and a clinical validation. SETTING The adult population of Värmland, a county in Sweden. SUBJECTS 4814 persons completed the survey and 206 the confirmative validation study. MAIN OUTCOME MEASURES Prevalence of respiratory symptoms, of asthma and COPD. RESULTS More than 40% reported respiratory symptoms. Wheeze was reported by 8.0%, shortness of breath by 11.4% and sputum production by 14.1%. Smoking was more common among women than among men. The prevalence of asthma was 8.2% and COPD 2.1%. Of persons with asthma, 33% were estimated to be undiagnosed, 67% used medication and nearly 60% attended primary health care services. CONCLUSION Respiratory symptoms as well as asthma were common in this study and equivalent to earlier findings. The difference between the epidemiologically estimated prevalence of asthma and the lower detection rate in primary health care can be explained by at least three factors: persons who did not seek any care, were underdiagnosed or attended other health care providers.

Asthma control in primary care in Sweden: a comparison between 2001 and 2005.

AIM To compare the degree of asthma control in 2001 and 2005 in a primary care setting in Sweden. METHOD Two similar questionnaire surveys were performed in 2001 and 2005 with 1,012 and 224 asthma patients aged 18-45 randomly selected from 42 and 56 primary health care centres, respectively. A classification of asthma control similar to the GINA guidelines was made using information obtained from the questionnaire. RESULTS In 2001, 36.6% had achieved asthma control, 23.8% were partly controlled and 39.6% uncontrolled. In 2005, the corresponding figures were 40.2%, 26.8% and 33.0%, respectively, with no difference between the two surveys (p=0.114). Uncontrolled asthma was more common in women (p<0.001 in the first and p<0.05 in the second survey) and smokers (p<0.01 in the first and p<0.01 in the second survey). The use of combination corticosteroid/long-acting bronchodilator inhalers had increased - 34.2% and 48.2%, respectively (p<0.001) - and many patients used their inhaled corticosteroids periodically. CONCLUSION In spite of treatment guidelines many patients in Swedish primary care still have insufficient asthma control.

Nurse-led multidisciplinary programme for patients with COPD in primary health care: a controlled trial.

AIM To investigate the effects of a nurse-led multidisciplinary programme (NMP) of pulmonary rehabilitation in primary health care with regard to functional capacity, quality of life (QoL), and exacerbations among patients with chronic obstructive pulmonary disease (COPD). METHOD A 1-year longitudinal study with a quasi-experimental design was undertaken in patients with COPD, 49 in the intervention group and 54 in the control group. Functional capacity was assessed using the 6-minute walking test, and quality of life (QoL) was assessed using the Clinical COPD Questionnaire. Exacerbations were calculated by examination of patient records. RESULTS No significant differences were found between the groups in functional capacity and QoL after 1 year. The exacerbations decreased in the intervention group (n = -0.2) and increased in the control group (n = 0.3) during the year after NMP. The mean difference of change in exacerbation frequency between the groups was statistically significant after one year (p=0.009). CONCLUSIONS The NMP in primary care produced a significant reduction in exacerbation frequency, but functional capacity and QoL were unchanged. More and larger studies are needed to evaluate potential benefits in functional capacity and QoL.

Symptoms and impact of symptoms on function and health in patients with chronic obstructive pulmonary disease and chronic heart failure in primary health care

Background Patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) seem to have several symptoms in common that impact health. However, methodological differences make this difficult to compare. Aim Comparisons of symptoms, impact of symptoms on function and health between patients with COPD and CHF in primary health care (PHC). Method The study is cross sectional, including patients with COPD (n=437) and CHF (n=388), registered in the patient administrative systems of PHC. The patients received specific questionnaires – the Memorial Symptom Assessment Scale, the Medical Research Council dyspnea scale, and the Fatigue Impact Scale – by mail and additional questions about psychological and physical health. Results The mean age was 70±10 years and 78±10 years for patients with COPD and CHF respectively (P=0.001). Patients with COPD (n=273) experienced more symptoms (11±7.5) than the CHF patients (n=211) (10±7.6). The most prevalent symptoms for patients with COPD were dyspnea, cough, and lack of energy. For patients with CHF, the most prevalent symptoms were dyspnea, lack of energy, and difficulty sleeping. Experience of dyspnea, cough, dry mouth, feeling irritable, worrying, and problems with sexual interest or activity were more common in patients with COPD while the experience of swelling of arms or legs was more common among patients with CHF. When controlling for background characteristics, there were no differences regarding feeling irritable, worrying, and sexual problems. There were no differences in impact of symptoms or health. Conclusion Patients with COPD and CHF seem to experience similar symptoms. There were no differences in how the patients perceived their functioning according to their cardinal symptoms; dyspnea and fatigue, and health. An intervention for both groups of patients to optimize the management of symptoms and improve function is probably more relevant in PHC than focusing on separate diagnosis groups.

The SELMA Study: A Birth Cohort Study in Sweden Following More Than 2000 Mother-Child Pairs.

BACKGROUND  This paper describes the background, aim and study design for the Swedish SELMA study that aimed to investigate the importance of early life exposure during pregnancy and infancy to environmental factors with a major focus on endocrine disrupting chemicals for multiple chronic diseases/disorders in offspring. METHODS The cohort was established by recruiting women in the 10th week of pregnancy. Blood and urine from the pregnant women and the child and air and dust from home environment from pregnancy and infancy period have been collected. Questionnaires were used to collect information on life styles, socio-economic status, living conditions, diet and medical history. RESULTS Of the 8394 reported pregnant women, 6658 were invited to participate in the study. Among the invited women, 2582 (39%) agreed to participate. Of the 4076 (61%) non-participants, 2091 women were invited to a non-respondent questionnaire in order to examine possible selection bias. We found a self-selection bias in the established cohort when compared with the non-participant group, e.g. participating families did smoke less (14% vs. 19%), had more frequent asthma and allergy symptoms in the family (58% vs. 38%), as well as higher education among the mothers (51% vs. 36%) and more often lived in single-family houses (67% vs. 60%). CONCLUSIONS These findings indicate that the participating families do not fully represent the study population and thus, the exposure in this population. However, there is no obvious reason that this selection bias will have an impact on identification of environmental risk factors.

The association between medical conditions and gender, well-being, psychosomatic complaints as well as school adaptability

The aim was to assess the association between medical conditions and gender, well‐being, psychosomatic complaints and school adaptability. The second aim was to determine whether self‐reported medical conditions should be included in class‐room questionnaires that deal with well‐being and risk behaviour.

Change in health status in COPD : a seven-year follow-up cohort study

Health status is a prognostic factor included in the assessment of chronic obstructive pulmonary disease (COPD). The aim of our study was to examine the associations of clinical factors with change in health status over a 7-year follow-up period. In 2005, 970 randomly selected primary and secondary care patients with a COPD diagnosis completed questionnaires including the Clinical COPD Questionnaire (CCQ); and in 2012, 413 completed the CCQ questionnaire again. Linear regression used difference in mean total CCQ score between 2005 and 2012 as the dependent variable. Independent variables were CCQ score at baseline 2005, sex, age, educational level, body mass index (BMI), smoking status, heart disease, diabetes, depression, number of exacerbations in the previous 6 months, dyspnoea (modified Medical Research Council (mMRC)). Health status worsened from mean total CCQ (s.d.) 2.03 (1.26) in 2005 to 2.16 (1.37) in 2012 (P=0.011). In linear regression with adjustment for baseline CCQ; older age, lower education, higher mMRC and BMI below 25 kg/m2 at baseline were associated with worsened health status in 2012. When sex, age and all statistically significant measures were included simultaneously in the analysis of the main study group, higher mMRC and BMI below 25 kg/m2 were were associated with deteriorated health status (P<0.0001). A higher level of dyspnoea and lower weight were associated with worse health status in COPD. Strategies for decreasing dyspnoea and awareness of the possible increased risk of worsening disease in under- and normal-weight COPD patients are clinically important.