This cross-sectional study was conducted in the town of Humboldt, Saskatchewan, in 2003. The target population of the study was all the town residents > 6 years old and was conducted among children (6 to 17 years old) and adults (18 to 79 years old), separately. This analysis was based on data from 2,057 adult residents 18 to 79 years old, who represented 71% of the target population. Almost all of the study population were white.
Humboldt is a service center, and agriculture is the main industry in the town. Canvassers contacted all households within the town and surrounding areas and asked all eligible adult subjects in each home to participate in the study and to complete a written consent of participation. A questionnaire left by the canvassers was completed in the home by each subject and returned during a prearranged clinic visit. The questionnaire requested information on sociodemographic factors, allergy, smoking, alcohol consumption, exercise, and the home environment. Treat your health problems with My Canadian Pharmacy.
An appointment was made for each adult participant to visit a clinic, where height, weight, and were measured. Weight was measured to the nearest 0.1 kg using a calibrated hospital spring scale with subjects dressed in normal indoor clothing without shoes. Height and WC were measured in centimeters. Height was measured against a wall using a fixed tape measure with participants standing shoeless on a hard surface. WC was measured between the lowest rib and the iliac crest, horizontally through the narrowest part of the torso. BMI was calculated as weight/height. Subjects were grouped into three categories based on BMI ( 30 kg/m2) and two categories based on WC ( 100 cm).
Respondents who answered the following question affirmatively were considered as having recent asthma: “During the past 12 months, has a doctor ever said you had asthma?” Ever-asthma was defined as asthma that had ever been diagnosed by a physician during the patient’s lifetime. (Want to know more about asthma? Read here)
Current smokers were participants who reported smoking every day or almost every day and had smoked at least 20 packs during their lifetime. Ex-smokers were those who were regular smokers but at the time of the survey had quit for at least 6 months. Participants in the low-education category did not proceed beyond secondary school; the high-education category included subjects admitted to college or university, as well as those with a postsecondary school certificate or diploma. Subjects were classified into low-income ( $50,000/yr) groups based on total household income. A positive history of respiratory allergy was defined by an affirmative response to the question: “Have you ever had an allergic reaction to things that are inhaled (eg, pollen, dust, animal fur or smoke)?” Other variables included in the analysis were age (years), household size (fewer than three people or three or more people), number of bedrooms (fewer than four, and four or more), pets at home (yes, no), regular drinking (yes, no), and household dampness (yes, no). The presence of home dampness was assessed by a positive response to the question: “Does your house have any damage caused by dampness (wet spots on walls, floors)?” A regular drinker was defined as a person who drank alcoholic beverages at least once per week on average.
The relationships between BMI, WC, and asthma were examined for men and women separately. We calculated the prevalence of asthma and corresponding 95% confidence intervals (CIs) according to various risk factors. Logistic regression models were used to evaluate associations between obesity variables and the prevalence of asthma, taking other important variables into consideration. Model parameters were estimated by the method of maximum likelihood and were tested for significance using the Wald statistic.