Using Multilevel Regression and Poststratification to Estimate Physical Activity Levels from Health Surveys.

BACKGROUND: Large-scale health surveys often consider sociodemographic characteristics and several health indicators influencing physical activity that often vary across subpopulations. Data in a survey for some small subpopulations are often not representative of the larger population. OBJECTIVE: We developed a multilevel regression and poststratification (MRP) model to estimate leisure-time physical activity across Brazilian state capitals and evaluated whether the MRP outperforms single-level regression estimates based on the Brazilian cross-sectional national survey VIGITEL (2018). METHODS: We used various approaches to compare the MRP and single-level model (complete-pooling) estimates, including cross-validation with various subsample proportions tested. RESULTS: MRP consistently had predictions closer to the estimation target than single-level regression estimations. The mean absolute errors were smaller for the MRP estimates than single-level regression estimates with smaller sample sizes. MRP presented substantially smaller uncertainty estimates compared to single-level regression estimates. Overall, the MRP was superior to single-level regression estimates, particularly with smaller sample sizes, yielding smaller errors and more accurate estimates. CONCLUSION: The MRP is a promising strategy to predict subpopulations' physical activity indicators from large surveys. The observations present in this study highlight the need for further research, which could, potentially, incorporate more information in the models to better interpret interactions and types of activities across target populations.

Clustering of Physical Activity and Sedentary Behavior Associated to Risk for Metabolic Syndrome in Older Adults.

This study aimed to investigate the clustering patterns of physical activity, sedentary time (ST), and breaks in ST, and the association between the identified clusters at risk for metabolic syndrome associated with obesity in older adults. Participants included 212 users of community health centers in Brazil. A questionnaire about sociodemographic characteristics was used to describe the sample, and physical activity, ST, and breaks in ST were evaluated using accelerometers. Waist circumference was measured as an indicator of the risk for metabolic syndrome. A two-step cluster analysis and logistic regression analysis were conducted. The following four clusters were identified: sitters (37.7%), inactive (28.3%), active (25.5%), and all-day sitters/lightly active (8.5%). Participants in the active cluster were 60% less likely to be at risk for metabolic syndrome. This study may contribute to a comprehensive understanding of which older adult groups need more attention in the context of community health centers.

Sedentary Behavior and Light Physical Activity Are Associated with Brachial and Central Blood Pressure in Hypertensive Patients.

BACKGROUND: Physical activity is recommended as a part of a comprehensive lifestyle approach in the treatment of hypertension, but there is a lack of data about the relationship between different intensities of physical activity and cardiovascular parameters in hypertensive patients. The purpose of this study was to investigate the association between the time spent in physical activities of different intensities and blood pressure levels, arterial stiffness and autonomic modulation in hypertensive patients. METHODS: In this cross-sectional study, 87 hypertensive patients (57.5 ± 9.9 years of age) had their physical activity assessed over a 7 day period using an accelerometer and the time spent in sedentary activities, light physical activities, moderate physical activities and moderate-to-vigorous physical activities was obtained. The primary outcomes were brachial and central blood pressure. Arterial stiffness parameters (augmentation index and pulse wave velocity) and cardiac autonomic modulation (sympathetic and parasympathetic modulation in the heart) were also obtained as secondary outcomes. RESULTS: Sedentary activities and light physical activities were positively and inversely associated, respectively, with brachial systolic (r = 0.56; P < 0.01), central systolic (r = 0.51; P < 0.05), brachial diastolic (r = 0.45; P < 0.01) and central diastolic (r = 0.42; P < 0.05) blood pressures, after adjustment for sex, age, trunk fat, number of antihypertensive drugs, accelerometer wear time and moderate-to-vigorous physical activities. Arterial stiffness parameters and cardiac autonomic modulation were not associated with the time spent in sedentary activities and in light physical activities (P > 0.05). CONCLUSION: Lower time spent in sedentary activities and higher time spent in light physical activities are associated with lower blood pressure, without affecting arterial stiffness and cardiac autonomic modulation in hypertensive patients.

Anthropometric indicators in older adults from Florianópolis: a population-based study conducted in 2002 and 2010 / Indicadores antropométricos em idosos de Florianópolis: estudo populacional em 2002 e em 2010

The objective of this study was to describe and compare specific anthropometric indicators in older adults from Florianópolis who participated in two population-based studies conducted in 2002 and 2010. A total of 865 older adults in 2002, and 1,657 older adults in 2010 were assessed for weight, height, body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR). Significant increases in body weight of 3.0 kg for men and 4.9 kg for women were identified from 2002 to 2010 (P < 0.05). The BMI also increased in both genders (+0.9 kg/m2 for men and +1.6 kg/m2 for women), while height increased only in women (+1.5 cm) (P < 0.05). No significant differences were observed for WC or WHtR. BMI classification revealed an increase in the prevalence of overweight/obesity in both genders (P < 0.05). However, when the subjects were classified based on WC and WHtR, no significant difference was observed between the two time points in either gender, highlighting the high percentage of older adults (> 70%) with inadequate WC and WHtR in 2002 as well as in 2010. The results suggest an increase in weight and BMI from 2002 to 2010 in older adults from Florianópolis. Furthermore, the prevalence of overweight/obesity characterized by BMI increased in women and men, whereas WC and WHtR remained unchanged between 2002 and 2010.

O objetivo do presente estudo foi descrever e comparar alguns indicadores antropométricos em idosos de Florianópolis em 2002 e em 2010, a partir de dois estudos populacionais. Para tanto, 865 idosos em 2002 e 1657 idosos em 2010, de ambos os sexos, foram avaliados quanto à massa corporal, estatura, índice de massa corporal (IMC), circunferência de cintura (CCint) e razão cintura estatura (RCEst). Acréscimos estatisticamente significantes de 3,0 e 4,9 kg no peso corporal foram identificados, respectivamente, para homens e mulheres, de 2002 para 2010 (P < 0,05). O IMC também aumentou em ambos os sexos (+0,9 kg/m2 para homens e + 1,6 kg/m2 para as mulheres), enquanto a estatura aumentou apenas para as mulheres (+1,5 cm) (P < 0,05). Para as variáveis CCint e RCEst não foram encontradas diferenças estatisticamente significantes. A partir da classificação do IMC, observou-se aumento da prevalência de sobrepeso/obesidade em ambos os sexos (P < 0,05). Entretanto, quando os sujeitos foram classificados a partir da CCint e da RCEst, nenhuma diferença estatisticamente significante foi observada entre os dois períodos do estudo, em nenhum dos gêneros, enfatizando a alta prevalência de idosos (> 70%) com CC e RCEst inadequadas, tanto em 2002 quanto em 2010. Os resultados sugerem que idosos de Florianópolis apresentaram aumento da massa corporal e IMC de 2002 para 2010; o percentual de idosos com sobrepeso/obesidade, classificados a partir do IMC, aumentou para ambos os sexos; e os indicadores CCint e RCEst não sofreram alterações de 2002 para 2010.

Anthropometric profiles of elite older triathletes in the Ironman Brazil compared with those of young Portuguese triathletes and older Brazilians.

The objective of this study was to describe the anthropometric profiles of elite older triathletes participating in the 2009 Ironman Brazil and to compare their somatotype, anthropometric and body composition characteristics with those of elite young triathletes and older non-athletes. The sample consisted of 64 males, divided into three groups: (1) older triathletes (n = 17), (2) young triathletes (n = 24), and (3) older non-athletes (n = 23). Somatotype was analysed according to the Carter and Heath ( 1990 ) method. Body mass index, sum of four skinfolds, percentage body fat, body fat mass, and fat-free mass were also estimated. Older non-athletes had higher endomorphy, sum of four skinfolds, fat percentage, and body fat mass than the athletes. Older athletes who participated in the Ironman and elite young triathletes had higher fat-free mass than older non-athletes. Older triathletes and older non-athletes were considered mainly endomorphic mesomorphs and young triathletes mainly ectomorphic mesomorphs. The findings that characterize the anthropometric profile of athletes in this sports modality could be used as a reference.