Exploring the obesity-asthma link: do all types of adiposity increase the risk of asthma?

BACKGROUND: Obesity and risk of asthma are linked. Different distributions of adiposity, such as visceral, subcutaneous or ectopic adiposity, may affect asthma risk differently. OBJECTIVE: To explore the association of different adiposity types with self-reported asthma, bronchial inflammation and lung function, accounting for possible effect modifiers, such as atopy and gender. METHODS: In a general population sample of 3471 persons aged 19-72, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured by ultrasound, and fat percentage by bio-impedance. Body mass index, waist circumference, waist-to-hip ratio (WHR), bronchial inflammation as fractional expiratory nitric oxide (FeNO), lung function [FEV(1) and forced vital capacity (FVC)], and atopy (specific IgE) were measured. RESULTS: All adiposity measures were associated with a higher risk of asthma. The risk estimates (odds ratios, OR, with 95% confidence interval, CI) of current asthma were of similar magnitude for all six adiposity measures ranging between 1.17, CI = 0.98-1.40 (SAT) and 1.51, CI = 1.17-1.95 (WHR). The adiposity-asthma associations were significantly stronger in non-atopics than in atopics. In non-atopics the risk estimates of current asthma ranged between 1.35 CI = 1.08-1.72 and 1.82 CI = 1.34-2.46 for SAT and WHR respectively. Consistent results were obtained using dichothomized adiposity measures (obese vs. non-obsese). The FVC and FEV(1) decreased significantly with increasing adiposity in both atopics and non-atopics, e.g. FVC decreased between 36 mL (CI = 10, 62 mL) and 155 mL (CI = 124, 186 mL) for one unit (standard error) increase of SAT and VAT respectively. Adiposity measures were not associated with atopy and not consistently associated with FeNO levels. CONCLUSIONS AND CLINICAL RELEVANCE: The effect of adiposity on asthma was mainly seen in non-atopics and did not appear to depend on the distribution of adiposity as reflected by the adiposity measures used in the present study. Increasing adiposity was associated with lower lung function independent of atopic status.

Determinants of serum tryptase in a general population: the relationship of serum tryptase to obesity and asthma.

BACKGROUND: Recent studies indicate that mast cells are more abundant in the obese state. Total serum tryptase (ST) is a marker of mast cell numbers or activity. Since obesity and asthma have been consistently linked in epidemiological studies, a possible higher mast cell activity in obesity could be a factor between the two conditions. The aim of this study was to investigate determinants of ST and whether a potential association between obesity and allergic respiratory disease would be influenced by levels of ST in obese persons. METHODS: Measurements of ST (ImmunoCAP Tryptase assay), atopy (skin prick test reactivity), methacholine bronchial hyperresponsiveness (BHR), body mass index (BMI) and serum lipids were performed in a general population of 1,216 persons aged 15-69 years. RESULTS: ST increased significantly with increasing BMI. The median ST level increased from 3.3 µg/l in persons with BMI <25 to 4.4 µg/l in persons with BMI >30, p < 0.0001. Age (p < 0.0001), male sex (p = 0.0009) and smoking (p = 0.022) were positively associated with ST, whereas alcohol consumption (p = 0.005) was inversely associated with ST. ST was not associated with atopy, symptoms of allergic respiratory disease or BHR. A positive association between symptoms of allergic respiratory disease and obesity (OR = 1.98, 95% CI = 1.25-3.14) was not influenced by obesity-related differences in ST. CONCLUSIONS: Increasing BMI was significantly associated with increasing ST and the prevalence of symptoms of allergic respiratory disease. However, mast cell activity/burden (assessed by ST levels) did not influence the association between BMI and asthma/rhinitis symptoms.

Size dependent catalysis with CTAB-stabilized gold nanoparticles.

CTAB-stabilized gold nanoparticles were synthesized by applying the seeding-growth approach in order to gain information about the size dependence of the catalytic reduction of p-nitrophenol to p-aminophenol with sodium borohydride. Five different colloidal solutions of stabilized gold nanoparticles have been characterized by TEM, AFM, UV-Vis, SAXS, and DLS for their particle size distributions. Gold nanoparticles (mean sizes: 3.5, 10, 13, 28, 56 nm diameter) were tested for their catalytic efficiency. Kinetic data were acquired by UV-Vis spectroscopy at different temperatures between 25 and 45 °C. By studying the p-nitrophenol to p-aminophenol reaction kinetics we determined the nanoparticle size which is needed to gain the fastest conversion under ambient conditions in the liquid phase. Unexpectedly, CTAB-stabilized gold nanoparticles with a diameter of 13 nm are most efficient.

The association of the 'additional height index' with atopic diseases, non-atopic asthma, ischaemic heart disease and mortality: a population-based study.

OBJECTIVE: Intrauterine growth has been associated with atopic conditions. Growth and adult height have been associated with cardiovascular disease, cancers and mortality but are highly genetic traits. The objectives of the study were as follows: first, to define a height measure indicating an individual's height below or above that which could be expected based on parental height (genetic inheritance) and growth charts. It was named 'the additional height index' (AHI), defined as (attained-expected) height; second, to investigate possible associations of AHI with atopic versus non-atopic health outcomes and with ischaemic heart disease (IHD) and IHD mortality. DESIGN: General population-based study. SETTING: Research centre. PARTICIPANTS: A random sample of 2656 men and women living in greater Copenhagen took part in the MONICA10 study (the Danish monitoring trends and determinants of cardiovascular disease). In total, 1900 participants with information of parental height were selected. OUTCOME MEASURES: Atopic sensitisation (serum IgE), questionnaire information of atopic dermatitis, rhinoconjunctivitis, asthma or wheezing, and registry-based diagnoses of IHD/IHD mortality from National Registries. RESULTS: Increasing levels of AHI were inversely associated with non-atopic asthma, non-atopic wheezing, IHD and IHD mortality (IHD-all). For one SD increase of AHI, the OR or HR with CI in adjusted analyses was non-atopic asthma OR=0.52 (0.36 to 0.74), non-atopic wheezing OR=0.67 (0.51 to 0.89), and IHD-all HR=0.89 (0.78 to 1.01). The level of AHI was higher among individuals with atopic dermatitis, allergic rhinoconjunctivitis and atopic sensitisation (all p values <0.001) compared with individuals without those conditions; however, the associations were not confirmed in adjusted analyses. CONCLUSIONS: Individuals with childhood conditions that led them to attain tallness higher than expected from their parents' height may be at lower risk of non-atopic asthma/wheeze and IHD/IHD mortality but possibly at higher risk of atopic conditions. The measure of tallness below or above the expected height could be a sensitive alternative to normal height in epidemiological analyses.

The relationship of serum triglycerides, serum HDL, and obesity to the risk of wheezing in 85,555 adults.

BACKGROUND: Asthma has been linked to obesity and the presence of the metabolic syndrome. OBJECTIVE: To explore which components of the metabolic syndrome that were associated with wheezing, a main symptom of asthma. Further, to explore whether these associations were different in individuals with and without rhinitis symptoms. METHODS: We used data from the Ibermutuamur Cardiovascular Risk Assessment Plan (ICARIA) including 85,555 Spanish workers (median age = 34, range = 16-75 years) with assessments of self reported wheezing and rhinitis symptoms. Fasting blood samples were analysed for serum triglyceride (s-TG), HDL (s-HDL) and glucose; blood pressure, waist circumference (WC) and body mass index (BMI) were measured. RESULTS: In mutually adjusted analyses including all components of the metabolic syndrome and possible confounders, elevated WC (or BMI), elevated s-TG and low s-HDL were significantly associated with wheezing. Odds ratio (OR) with confidence interval (CI) were: elevated WC = 1.54 (1.46-1.62), elevated s-TG = 1.24 (1.18-1.30), low s-HDL = 1.17 (1.12-1.22). These associations were stronger in individuals without than in those with rhinitis symptoms, OR's (CI's) were WC = without rhinitis 1.70 (1.57-1.85) vs. with rhinitis 1.47 (1.37-1.58). Elevated s-TG = without rhinitis 1.36 (1.26-1.46) vs. with rhinitis 1.21 (1.13-1.29). Low s-HDL = without rhinitis 1.24 (1.15-1.34) vs. with rhinitis 1.11 (1.04-1.18). CONCLUSIONS: High s-TG and low s-HDL were associated with wheezing after adjustment for adiposity. This may substantiate elevated s-TG and lowered s-HDL as markers or inducers of inflammation associated disease. The study supports the notion that these biochemical markers have differential effects on different types of wheezing.

Serum 25(OH)D and incident type 2 diabetes: a cohort study.

BACKGROUND/OBJECTIVES: Mild to moderate vitamin D insufficiency has been proposed as a risk factor for several common chronic diseases including type 2 diabetes. This study aimed to examine the association between serum 25-hydroxy vitamin D (25(OH)D) and incident diabetes. SUBJECTS/METHODS: The MONICA10 cohort consists of 2656 participants (men and women aged 41-71 years) who participated in a 10-year follow-up examination during 1993-1994 as part of the MONICA 1 population survey. A total of 2571 participants free of diabetes at baseline and with successful measurement of serum 25(OH)D were included in the current study. The Danish National Diabetes register enabled identification of 288 cases of incident diabetes during follow-up (median: 16.4 years). Data were analysed by Cox proportional hazard models and associations were expressed as hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: Serum 25(OH)D was inversely associated with incident diabetes adjusted for potential confounders (HR per 25 nmol/l=0.83; 95% CI: 0.72-0.95; P=0.009). A statistically significant interaction was observed between 25(OH)D and waist circumference (WC) (P(interaction)=0.042) suggesting an association in persons with a high WC (HR (95%CI) per 25 nmol/l=0.74 (0.63-0.88), 218 incident cases) and not in persons with a normal WC (HR (95%CI) per 25 nmol/l=0.98 (0.78-1.24), 70 incident cases). CONCLUSIONS: Low serum 25(OH)D was associated independently with incident diabetes. The inverse association was only found in overweight-obese and not in normal weight individuals, suggesting that obesity may modify the effect of vitamin D status on the risk of diabetes.

Increasing seroprevalence of Clostridium difficile in an adult Danish general population.

The incidence of Clostridium difficile-associated infections is increasing, but it remains to be defined whether any change in the seroprevalence of C. difficile has also occurred. In a population-based study of the general adult population, 734 subjects, aged 15-69 years, were examined on two occasions 8 years apart (1990 and 1998) for the presence of antibodies against C. difficile in serum. The overall seroprevalence of C. difficile increased significantly from 19% in 1990 to 27% in 1998 (P<0.0001). The seroprevalence increased with increasing age in both 1990 and 1998, but the increase was about four times higher in 1998 than in 1990. In conclusion, the observed increase in seroprevalence suggests a higher exposure to C. difficile in the general Danish adult population.

[Stress reactions in clinically healthy sows at the time of birth and their relationship to the CK test]. / Belastungsreaktionen bei klinisch gesunden Sauen zur Zeit der Geburt und ihre Beziehung zum CK-Test.

Concentrations of the enzymes creatine kinase (CK) and aspartate aminotransferase (ASAT/GOT) were determined in plasma of 100 gilts and 175 sows at the 112. day of pregnancy and one day after parturition. Gilts and sows were divided into a stress resistant (n = 146) and a stress susceptible group (n = 129) following the creatine-kinase-test carried out after the performance test period at a body weight of 90 kg (CK-90). Stress susceptible gilts and sows showed higher CK-values before and especially after parturition than stress resistant ones. Significant correlations were demonstrable between CK-90 and the CK values before and after parturition (r = 0.5). Regarding body temperature, respiration rate and heart frequency as well as the percentage of stillborn piglets, the two groups of sows did not differ from each other. The increase of enzyme activities after parturition was not influenced by prophylactic treatment with prostaglandin-F2-alpha or beta receptor blocking agent. The beta blocking agent Carazolol, however, caused a transient depression of heart rate after parturition.