Comportamento sedentário em mulheres adultas e sua associação com variáveis ambientais e individuais: um estudo de base populacional

Abstract

In the past decade, a number of studies have investigated sedentary behaviour (SB), that is, activities performed while awake in a sitting or lying position and that involve reduced energetic expenditure. Its consequences for the health of individuals have also been examined. Results from prospective studies have shown that the longer the time spent on SB, the greater the risk of developing diabetes, cardiovascular disease, metabolic syndrome, and death. The general objective of this study was to evaluate the association of environmental and individual variables with SB in adult women living in the municipality of São Leopoldo, Rio Grande do Sul, Brazil. In order to meet the general objective, two sub-studies were developed, both with a cross-sectional design. The first study aimed to describe SB in the leisure time (LSB), occupational (OSB) and transport (TSB) domains and to determine the factors associated with excess sedentary behaviour (ESB) in those domains (ELSB, EOSB and ETSB, respectively). A representative sample of 1,126 women, aged 20-69 years, from the municipality of São Leopoldo was investigated. Information regarding SB and demographic, socioeconomic, behavioural and health-related variables was obtained using a questionnaire that was completed using an interview format. Values above the median were considered to be ESB. The associations were tested using Poisson regression with robust error variance. The mean and interquartile intervals, in min/day, for LSB, OSB and TSB were 163.9 (86.6-2,710.5); 54.1 (0-257.1) and 17.1 (5.7-37.3), respectively. The probability of ELSB increased with the level of education and was higher among women who were not employed, who had no children in the household and who were smokers. For EOSB and ETSB, probabilities increased inversely with age and were higher among white women; these probabilities also increased with economic class, level of education and income. The probability of ETSB also increased with the number of cars per household and was 30% lower among women who were not employed. The longest time spent in SB was observed in the leisure time domain. The associations differed by domain. In the second study (Article 2), the objective was to assess the association between environmental variables in the neighbourhood and excess transport (ETSB) and excess leisure time (ELSB) sedentary behaviours among study participants. Data from 1,079 women living in 44 neighbourhoods were considered. Each neighbourhood was determined by drawing a 400-m buffer around the median point of the participants’ homes. The evaluation of the neighbourhoods was performed through audits and the use of government data. The data on SB and the other variables used were obtained from the first study. A multilevel logistic regression analysis was conducted. In the adjusted analysis, women who lived in neighbourhoods with a higher percentage of terrain slopes and fewer public recreation areas per inhabitant had significantly (p ≤ 0.05) increased chances of exhibiting ETSB and ELSB, with increases of 50% and 40%, respectively. The results of the two studies demonstrated that a) interventions should be developed with consideration for the specifics of each SB domain, and b) some aspects of the neighbourhood environment, like terrain slopes and public recreation areas, may interfere with specific types of SB, indicating that neighbourhood improvements could reduce women’s SB.