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Title: The role of physical activity and diet on the incidence of obesity and hypertension: a cohort study
Author: Camões, Miguel
Defense Date: 2010
Publisher: Universidade do Porto, Faculdade de Medicina
Citation: Camões, Miguel (2010) - The role of physical activity and diet on the incidence of obesity and hypertension: a cohort study. Porto: Faculdade de Medicina. Tese de Doutoramento em Saúde Pública
Abstract: We aimed to evaluate prospectively the independent role of different types and intensities of physical activity (PA) as well as nutrient intake and dietary patterns in the incidence of obesity and hypertension. To accomplish our general objective, we performed 5 studies with the following specific objectives: 1. To assess the validity, reproducibility and seasonal bias on usual PA reporting of an adapted version of the EPIC PA questionnaire, designed to measure the different types of PA in Portuguese adults. 2. To describe the relationship between dietary intake and different levels and types of PA. 3. To provide overall and central obesity incidence estimates by gender, age and educational level in an urban Portuguese population. 4. To evaluate the role of different types of PA and diet on overall and central obesity incidence. 5. To evaluate longitudinally the role of PA (type and intensity) and diet (DASH score, nutrient and food intake) on hypertension incidence. Methods Participants are part of a prospective cohort - the EPIPorto study, comprising a representative sample of 2485 Portuguese adults (61.8% females), aged 18-92 years, resident in Porto. Participants were recruited by random digit dialing using households as the sampling unit. The local ethics committee approved the study protocol. Study participants were invited to visit the Department of Hygiene and Epidemiology of the University of Porto Medical School to be evaluated. Participants’ first evaluation was performed between 1999 and 2003 and the re-evaluation of the cohort was done between 2005 and 2008. Regarding the baseline evaluation, a participation proportion of 70% was achieved and 67.7% of the total cohort was re-evaluated by December 2008. Evaluations were done by trained interviewers using a standard structured questionnaire, comprising information on social, demographic, personal and family medical history, and behavioural characteristics. Studies I and II were based on cross-sectional data and the studies III, IV and V used longitudinal information. For exposure measurement, validated questionnaires were used to assess PA and dietary intake during the previous year. PA questionnaire explores all professional, domestic and leisure-time physical activities, detailing the duration and intensity for each activity. To calculate PA energy expenditure, we used standard metabolic energy equivalent task (MET) values. Full-day energy expenditure included energy expended in all activities during the entire day (rest, professional, household chores and leisure-time activities), while occupational activities included professional and household activities. Leisure-time PA included sedentary leisure-time activities and different types of exercise. After having assessed total energy expenditure (TEE) based on the PA questionnaire and considering the individual Resting Metabolic Rate (RMR), we calculated the Physical Activity Level (PAL=TEE/RMR). A food-frequency questionnaire (FFQ) was used to evaluate dietary intake. The FFQ comprises 82 food and beverage-item categories, as well as a frequency section. Participants were asked to indicate the average frequency of consumption during the preceding year, as well as the portion size based on a photograph manual with three size options (small, medium, large) for each food item. Data on different nutrient intake and food consumption were provided and different patterns of intake, defined a priori, were constructed, such as the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH diet). The outcomes of interest in this study were obesity and hypertension. To obtain updated information regarding overall overweight/obesity, central obesity and hypertension onset, objective evaluations of weight, height, waist circumference (WC) and blood pressure, were done, according to standard procedures. Overall obesity was defined through Body Mass Index (BMI), and participants were classified as underweight to normal weight (BMI<25.0 kg/m2); overweight (BMI 25.0-29.9 kg/m2); and obese (BMI!30.0 kg/m2); the categorization used for classifying individuals with central obesity was: WC>102 cm for men and WC>88 cm for women. Hypertension was defined as a Systolic Blood Pressure >=140 mmHg and/or Diastolic Blood Pressure >=90 mmHg and/or current antihypertensive drug therapy.
Peer review: yes
Appears in Collections:DCDEF - Teses de Doutoramento

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