Previous prospective studies have shown inconsistent associations between serum 25-hydroxyvitamin D [25(OH)D] level and lung cancer incidence. The aim of the present study was to explore the associations of serum 25(OH)D levels with incidence of lung cancer overall and different histologic types. We performed a population-based prospective case-cohort study including 696 incident lung cancer cases and 5804 individuals in a subcohort who participated in the second survey of the Nord-Trøndelag Health Study in Norway. Cox proportional hazards regression models counting for the case-cohort design were used to estimate hazard ratios (HRs) with 95% confidence interval (CIs) for lung cancer overall or histologic types in relation to serum 25(OH)D levels. Compared with the fourth season-specific quartile of 25(OH)D (median 68.0 nmol/L), lower 25(OH)D levels were not associated with the incidence of overall, small or squamous cell lung cancer. However, the risk of adenocarcinoma was lower in the second and third quartiles (median 39.9 and 51.5 nmol/L) compared with the fourth quartile, with HRs of 0.63 (95% CI 0.41-0.98) and 0.58 (0.38-0.88), respectively. The associations of lower levels of 25(OH)D with a reduced risk of adenocarcinoma were only observed in the overweight/obese subjects [HRs for second and third quartiles: 0.40 (0.22-0.72) and 0.50 (0.27-0.92)] but not in the normal weight subjects [HRs: 0.95 (0.52-1.75) and 0.60 (0.32-1.10)]. Serum 25(OH)D levels were not associated with the risk of lung cancer in general. The observation that lower 25(OH)D levels were associated with a lower risk of adenocarcinoma should be interpreted with caution.
We assessed the relationship between very low birth weight (VLBW) (or= 9 days was the only remaining significant risk factor for a history of asthma (adjusted OR 6.7, 95%CI 1.0-44). The VLBW children who required mechanical ventilation during the neonatal period were more likely to have bronchial hyperresponsiveness than those not requiring mechanical ventilation (60% vs. 28%, p = 0.050). The spirometric values were similar among the VLBW and the term children at 12 years. Very low birth weight was not significantly related to allergic rhinoconjunctivitis, eczema or positive skin prick tests. Furthermore, the levels of IL-4, IL-5 and IFN-gamma in stimulated cell cultures were similar in the VLBW and the term children. A history of asthma by 12 years of age was twice as common among the VLBW as the term children, and neonatal oxygen supplementation seemed to be associated with the increased risk. Furthermore, mechanical ventilation during the neonatal period was associated with bronchial hyperresponsiveness at age 12. Very low birth weight per se was not, however, related to atopy.
Cod liver oil is an important source of vitamin D, but also contains other fat-soluble components such as vitamin A. Before 1999, the cod liver oil formula in Norway contained a high concentration of vitamin A (1000 µg per 5 ml). High vitamin A status is associated with increased risks of several chronic diseases.
To investigate the association between cod liver oil intake and asthma development.
In the Nord-Trøndelag Health Study, a total of 25 616 Norwegian adults aged 19-55 years were followed up from 1995-1997 to 2006-2008. Current analysis based on 17 528 subjects who were free of asthma and had complete information on cod liver oil intake at baseline. Cod liver oil intake was defined as daily intake = 1 month during the year prior to baseline. Incident asthma was reported as new-onset asthma during the 11-year follow-up.
Of the 17 528 subjects, 18% (n=3076) consumed cod liver oil daily for = 1 month over the past year. Cod liver oil intake was significantly associated with incident asthma with an OR of 1.62 (95% CI 1.32 to 1.98) after adjustment for age, sex, daily smoking, physical activity, education, socio-economic status, family history of asthma, and body mass index (BMI). The positive association was consistent across age (
Experimental studies suggest that vitamin D modulates the activity of adipocytes. The authors examined baseline serum 25-hydroxyvitamin D (25(OH)D) level in relation to prevalent and cumulative incident obesity in Norway. A cohort of 25,616 adults aged 19-55 years participated in both the second and third surveys of the Nord-Trøndelag Health Study (HUNT 2 (1995-1997) and HUNT 3 (2006-2008)). Serum 25(OH)D levels measured at baseline and anthropometric measurements taken at both baseline and follow-up were available for a random sample of 2,460 subjects. Overall, 40% of the 2,460 subjects had a serum 25(OH)D level less than 50.0 nmol/L, and 37% had a level of 50.0-74.9 nmol/L. The prevalence and cumulative incidence of obesity, defined as body mass index (weight (kg)/height (m)(2)) =30, were 12% and 15%, respectively. Lower serum 25(OH)D level was associated with a higher prevalence of obesity. In the 2,165 subjects with baseline BMI less than 30, a serum 25(OH)D level less than 50.0 nmol/L was associated with a significantly increased odds ratio for incident obesity during follow-up (adjusted odds ratio = 1.73, 95% confidence interval: 1.24, 2.41). When prevalent and incident obesity were classified according to waist circumference (=88 cm for women, =102 cm for men), similar results were obtained. In addition to prevalent obesity, a serum 25(OH)D level less than 50.0 nmol/L was significantly associated with new-onset obesity in adults.
Vitamin D deficiency occurs worldwide. Winter season and high Body Mass Index (BMI) are associated with low levels of serum 25-hydroxyvitamin D (25(OH)D). We estimated the prevalence of vitamin D deficiency in a Norwegian adult population and examined factors associated with vitamin D deficiency. A cohort of 25,?616 adults (19-55 years) who participated in both the second and third Nord-Trøndelag Health Study (HUNT 2 (1995-1997) and HUNT 3 (2006-2008)) was established in a previous study. A 10% random sample of the cohort population was recruited for serum 25(OH)D measurements (n=2584), which was used for the current cross-sectional study. Vitamin D deficiency was defined as serum 25(OH)D level
Measures of body mass index (BMI) and waist circumference define general obesity and abdominal obesity respectively. While high BMI has been established as a risk factor for asthma in adults, waist circumference has seldom been investigated. To determine the association between BMI, waist circumference and incident asthma in adults, we conducted a prospective study (n=23,245) in a population living in Nord-Trøndelag, Norway in 1995-2008. Baseline BMI and waist circumference were measured and categorised as general obesity (BMI =30.0 kg·m(2)) and abdominal obesity (waist circumference =88 cm in females and =102 cm in males). Incident asthma was self-reported new-onset cases during an 11-yr follow-up period. Odds ratios for asthma associated with obesity were calculated using multivariable logistic regression. General obesity was a risk factor for asthma in females (OR 1.96, 95% CI 1.52-2.52) and males (OR 1.84, 95% CI 1.30-2.59). In females, after additional adjustment for BMI, abdominal obesity remained a risk factor for asthma development (OR 1.46, 95% CI 1.04-2.05). Abdominal obesity seems to increase the risk of incident asthma in females in addition to BMI, indicating that using both measures of BMI and waist circumference in females may be a superior clinical assessment for asthma risk than any measure alone.
Comment In: Eur Respir J. 2013 Feb;41(2):253-423370797
How different Global Initiative for Chronic Obstructive Lung Disease (GOLD) classifications of chronic obstructive pulmonary disease (COPD) predict mortality is unclear.
To examine the association of spirometric GOLD grades and the new ABCD groups with mortality, and to compare their informativeness in relation to mortality.
We studied 1540 people with post-bronchodilator COPD who participated in the Norwegian Nord-Tr?ndelag Health Study 1995-1997 and were followed up on all-cause mortality until May 2012. The associations of spirometric GOLD grades and ABCD groups with mortality were estimated by sex specific adjusted HRs from Cox regression and standardised mortality ratios. To assess the informativeness of spirometric GOLD grades and ABCD groups at predicting mortality we used the difference in twice the log-likelihood of a Cox regression model with and without each COPD classification.
The distribution of participants was 28% in GOLD 1, 57% in GOLD 2, 13% in GOLD 3 and 2% in GOLD 4, in contrast to 61% in group A, 18% in group B, 12% in group C and 10% in group D. During a median of 14.6 years of follow-up, 837 people (54%) died. Mortality increased gradually from GOLD 1 to 4, while it was generally similar in groups A and B, and in groups C and D. Spirometric GOLD grades were substantially more informative than ABCD groups at predicting mortality.
Spirometric GOLD grades predicted mortality better than the new ABCD groups among people with COPD from a Norwegian general population.
The hypertonic saline challenge test is the recommended method to assess bronchial hyperresponsiveness in the International Study of Asthma and Allergies in Childhood (ISAAC). The sensitivity of this procedure to assess asthma symptoms, however, has been reported to vary among study centers. The purpose of our study was to evaluate the value of this provocation test in an epidemiological survey in children, and to relate the degree of bronchial hyperresponsiveness to the severity of asthma symptoms. All 11-13-year-old children from 16 randomly selected schools in Linköping, Sweden received a questionnaire regarding respiratory symptoms and allergic disease. Skin prick tests with eight inhalant allergens were performed. In addition, all children with wheeze over the past 12 months (current wheeze) and a random sample of children without current wheeze were invited to perform hypertonic saline provocation tests. A complete data set was available for 170 children, including 50 with and 120 without current wheeze. Bronchial hyperresponsiveness (BHR) was defined as at least 15% decline in FEV1. The degree of BHR was represented by the response/dose ratio, i.e. the fall in FEV1 divided by total dose of inhaled saline. The severity of asthma symptoms was classified by the number of wheezing episodes over the past 12 months. 'Asthma ever' was defined by a combination of symptoms in the questionnaires. Children with 'asthma ever' and current wheeze were considered as having current asthma. Current atopic asthma was defined as current asthma with at least one positive skin prick test. The sensitivity of the procedure to detect 'asthma ever', current asthma and current atopic asthma was 62, 61 and 83%, and the specificity 83, 81 and 60%, respectively. The positive challenge rate was 52, 34, 13 and 7% among current wheezers, previous wheezers, non-wheezers with a history of allergy and healthy children. The degree of bronchial hyperresponsiveness increased with the number of wheezing episodes. Thus, the median and range of the response/dose ratio were 4.8%/ml (2.1-14.8), 2.6%/ml (0.7-8.6) and 1.3%/ml (0.8-2.7), respectively, for children with >/= 4 episodes, 1-3 episodes and no wheezing episodes over the past 12 months (p
To explore potential associations between vitamin D status and risk of chronic low back pain (LBP) in a Norwegian cohort, and to investigate whether relationships depend on the season of blood sample collection.
A nested case-control study in a prospective data set.
The Norwegian community-based Nord-Trøndelag Health Study (HUNT). Data were collected in the HUNT2 (1995-1997) and HUNT3 (2006-2008) surveys.
Chronic LBP, defined as LBP persisting at least 3 months continuously during the past year.
Among individuals aged 19-55 years without LBP in HUNT2, a data set was generated including 1685 cases with LBP in HUNT3 and 3137 controls without LBP.
Blood samples from the participants collected in HUNT2 were analysed for serum 25-hydroxyvitamin D (25(OH)D) level. Associations with LBP in HUNT3 were evaluated by unconditional logistic regression analysis with adjustment for age, sex, work status, physical activity at work and in leisure time, education, smoking, and body mass index.
No association between vitamin D status and risk of chronic LBP was found in the total data set (OR per 10?nmol/L 25(OH)D=1.01, 95%?CI 0.97 to 1.06) or in individuals with blood samples collected in summer/autumn (OR per 10?nmol/L 25(OH)D=0.99, 95%?CI 0.93 to 1.06). For blood samples drawn in winter/spring, associations differed significantly between women and men (p=0.004). Among women a positive association was seen (OR per 10?nmol/L 25(OH)D=1.11, 95%?CI 1.02 to 1.20), but among men no significant association was observed (OR per 10?nmol/L 25(OH)D=0.90, 95%?CI 0.81 to 1.01).
Overall, no association between vitamin D status and risk of LBP was demonstrated. The association suggested in women for the winter/spring season cannot be regarded as established.
Anxiety or depression symptoms may increase the risk of developing asthma, and their interaction with obesity is not known. We aimed to assess the association of anxiety or depression symptoms and the joint association of these symptoms and obesity with incident asthma.
We conducted a prospective cohort study of 23 599 adults who were 19-55 years old and free from asthma at baseline in the Norwegian Nord-Trøndelag Health Study. The Hospital Anxiety and Depression Scale was used to measure anxiety or depression symptoms. Obesity was defined as a body mass index=30.0 kg/m2. Incident asthma was self-reported new cases of asthma during the 11-year follow-up.
Having anxiety or depression symptoms was associated with incident asthma [odds ratio (OR) 1.39, 95% confidence interval (CI) 1.09-1.78). Obese participants with anxiety or depression symptoms had a substantially higher risk of incident asthma (OR 2.93, 95% CI 2.20-3.91) than any other group (non-obese participants without anxiety or depression symptoms [reference], non-obese participants with anxiety or depression symptoms (OR 1.20, 95% CI 1.00-1.45) and obese participants without anxiety or depression symptoms (OR 1.47, 95% CI 1.19-1.82)]. The relative excess risk for incident asthma due to interaction between anxiety or depression symptoms and obesity was 1.26 (95% CI 0.39-2.12).
This study suggests that having anxiety or depression symptoms contributes to the development of asthma in adults. The risk of asthma may be further increased by the interaction between anxiety or depression symptoms and obesity.