Systematic review and meta-analysis on population attributable fraction for physical inactivity to dementia

INTRODUCTION

The number of cases of dementia attributable to physical inactivity remains unclear due to heterogeneity in physical inactivity definitions and statistical approaches used.

METHODS

Studies that used population-based samples to estimate the population attributable fraction (PAF) of physical inactivity for dementia were included in this review. Weighted PAFs were adjusted for communality among the risk factors (i.e., inactive persons may also share other risk factors) analyzed. Values were reported as percentage (%) of cases of dementia attributable to physical inactivity.

RESULTS

We included 22 studies. The overall impact of physical inactivity, defined by any criteria, on dementia ranged from 6.6% (95% CI: 3.6%, 9.6%; weighted) to 16.6% (95% CI: 14.4%, 18.9%; unweighted). Studies using the WHO criterion for physical inactivity estimated a higher unweighted impact (β = 7.3%; 95% CI: 2.0%, 12.6%) than studies using other criteria.

DISCUSSION

Conservatively, one in 15 cases of dementia may be attributable to physical inactivity, defined by any criteria.

Protocol for Objective Measurement of Infants' Physical Activity using Accelerometry

PURPOSE

This study aimed to evaluate methods for infants' physical activity measurement based on accelerometry, including the minimum number of measurement days and placement of a wrist or ankle device. We also evaluated the acceptability of the device among infants and mothers.

METHODS

A cross-sectional mixed-methods study was conducted on a convenience sample of 90 infants. Physical activity was measured using the Actigraph GT3X+ accelerometer placed on the wrist and/or ankle for 7 consecutive days (worn for 24 h), and a qualitative interview was performed to verify acceptability. The intraclass correlation coefficient (ICC) method and the Bland and Altman's dispersion diagram were used to verify the minimum number of measurement days. All analyses were stratified by walking status.

RESULTS

The mean (SD) age was 12.9 (1.70) months; the mean acceleration varied between 25.8 mg (95% confidence interval (CI), 14.3-52.7) and 27.3 mg (95% CI, 17.9-44.5) using the wrist placement, and between 24.9 mg (95% CI, 10.6-48.4) and 26.2 mg (95% CI, 11.7-65.6) using the ankle placement. The ICC results showed a lower acceleration variability between days among infants incapable of walking; they achieved an ICC of 0.80 with 1 d of measurement in both placements. Among those capable of walking, the minimum number of days to achieve an ICC of 0.80 was 2 d measured at the wrist (0.85; 95% CI, 0.71-0.93) and 3 d measured at the ankle (0.92; 95% CI, 0.84-0.96). The qualitative results pointed to the wrist placement as the preferred placement among the overall sample.

CONCLUSIONS

Two and three measurement days with the accelerometer placed on the wrist and ankle, respectively, seemed to adequately represent a week of measurement. The accelerometer placed on the wrist had better acceptance by the infants and mothers.

Fatores considerados pela população como mais importantes para manutenção da saúde

OBJETIVO: Analisar os fatores que adultos e idosos consideram como mais importantes para manutenção da saúde. MÉTODOS: Estudo transversal realizado com 4.060 adultos e 4.003 idosos residentes em áreas de abrangência de 240 unidades básicas de saúde das regiões Sul e Nordeste, em 2005. Um cartão com figuras e frases referentes a sete fatores relacionados com o risco de doenças e agravos não transmissíveis era mostrado aos indivíduos para que indicassem o fator mais relevante para a saúde. Os fatores eram: manter uma alimentação saudável, fazer exercício físico regularmente, não tomar bebidas alcoólicas em excesso, realizar consultas médicas regularmente, não fumar, manter o peso ideal e controlar ou evitar o estresse. As análises foram ajustadas por regressão de Poisson com cálculo de razões de prevalência ajustadas, intervalos com 95% de confiança, e valores de significância usando os Testes de Wald para heterogeneidade e tendência linear. RESULTADOS: Os fatores mais freqüentemente indicados pelos adultos foram: alimentação saudável (33,8%), realizar exercício físico (21,4%) e não fumar (13,9%). Entre os idosos, os fatores mais relatados foram: alimentação saudável (36,7%), não fumar (17,7%) e consultar o médico regularmente (14,2%). Foram observadas diferenças entre os fatores citados conforme a região geográfica, variáveis demográficas, socioeconômicas e de saúde. CONCLUSÕES: A maioria de adultos e idosos, de ambas regiões, reconhece e indica a necessidade de manter uma alimentação saudável e de não fumar como medidas mais importantes para manutenção da saúde. Estratégias de educação em saúde devem considerar essas características dos indivíduos para estimular medidas específicas a serem adotadas para cada segmento populacional.

Infant feeding and obesity at 11 years: prospective birth cohort study

OBJECTIVE

To evaluate the association between breastfeeding duration, introduction of solid or semi-solid foods before four months of age and overweight/obesity at 11 years.

METHODS

Prospective population-based birth cohort study, including 1 204 adolescents aged 11 years who were born in Pelotas (Brazil), in 1993, and were previously interviewed at birth, six and 12 months of age. Five explanatory variables were used: duration of any breastfeeding, duration of exclusive or predominant breastfeeding, ever breastfeeding, introduction of solid or semi-solid foods before four months of age, and feeding pattern at four months of age. Risk of overweight was defined as body mass index (BMI) > or = 85(th) percentile, and obesity was defined as BMI > or = 85(th) percentile plus triceps and subscapular skinfolds > or = 90(th) percentile, using the National Center for Health Statistics curves.

RESULTS

The prevalence of risk of overweight and obesity at 11 years were 23.2% and 11.6%, respectively. The lowest prevalence of both outcomes was found among subjects who were breastfed for one to three months. However, tests for linear trend or heterogeneity did not result in a significant association between breastfeeding indicators and anthropometry at 11 years. Adjustment for sex, skin color, birth weight, maternal schooling, smoking during pregnancy and maternal pre-pregnancy BMI did not alter the findings.

CONCLUSIONS

Our results do not support the hypothesis that breastfeeding has a long-term lasting effect on anthropometry in this population.