Associations of Frailty and Physical Function with a Daily Activities Measured by a Pattern-Recognition Activity Monitor: An Isotemporal Substitution Analysis in the IMPACT65+ Study.

OBJECTIVES: The aims of this study were (i) to examine the independent associations of the time spent in daily activities measured by multi-sensor pattern-recognition with frailty and physical functioning (PF); and (ii) to analyze how relocating time between these daily activities is associated with frailty and PF in a sample of older adults. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: The study sample consists of 436 (287 women) high-functioning community-dwelling older adults, aged 65 to 92 years, who participated in the IMPACT65+ Study. MEASUREMENTS: Frailty was calculated as a continuous measure; based on the five widely recognized Fried's criteria. PF was assessed using the SF-12 questionnaire. The time in daily activities was assessed by the Intelligent Device for Energy expenditure and Activity (IDEEA). Independent associations of daily activities with frailty and PF were examined using linear regression models adjusting for potential confounders. The isotemporal substitution models for estimate the effect of replacing time in one activity with the same amount of time in another activity while holding wake time constant. RESULTS: Time spent lying was directly associated, while time in walk at average and brisk pace was inversely associated with frailty. The independent associations for PF were similar to lying, walk at average pace and walk at brisk pace. Isotemporal substitution analyses revealed a clear beneficial effect of hypothetically replacing 30 min/day of sedentary behaviors or light physical activity by the same amount of moderate-to-vigorous physical activity for frailty and PF. CONCLUSION: This is the first study examining the activity-specific and isotemporal association of daily activities with frailty and PF in older adults. Isotemporal substitution analyses showed that replacing sedentary behaviors (lie, recline, passive sit) by light-intensity activities (active sit, stand and walk at slow pace), as well as light-intensity activities by activities at MVPA such as walk at brisk pace, may produce theoretical improvements in frailty and PF. These findings are important for the development of effective interventions focused on reducing age-related frailty and declines in PF.

Criterion-related validity of self-report walking time from the EPIC questionnaire in older adults.

Tools for measuring walking time make use of objective and subjective methods. One subjective approach is to administer physical activity questionnaires (PAQ), mainly because they are inexpensive and easy to give to large groups. The European Prospective Investigation into Cancer and Nutrition (EPIC) study has a brief PAQ (EPIC-PAQ) and includes one question referencing walking time. The objective of this study was to assess the validity of the question about time spent walking included in the EPIC-PAQ. The sample included 200 older adults (113 women). To assess daily walking time, participants responded to the EPIC-PAQ in an interview and wore a portable gait analysis system and physical activity monitor for 48 consecutive hours in free-living condition. Results indicated that the mean of bias between the EPIC-PAQ and objetive measurement was -64.6 min/day. Also, the correlation was low compared to an objective measurement (rho = 0.196) and was positively correlated with the time spent at speeds below 2.5 mph but the correlation was low (slow walking rho = 0.154 and pace walking rho = 0.163). The EPIC-PAQ shows low correlations with the objective measurement of walking time, that suggests it may be inaccurate and affecting the estimate of the EPIC-PAQ's PA energy expenditure in this age group.

Independent and combined influence of neonatal and current body composition on academic performance in youth: The UP & DOWN Study.

BACKGROUNDS: Unhealthy body composition is a cause for concern across the lifespan. OBJECTIVE: The objective of this study was to examine the independent and combined associations between neonatal and current body composition with academic performance among youth. METHODS: This cross-sectional study was conducted with a total of 1557 youth (745 girls) aged 10.4 ± 3.4 years. Birth weight and length at birth were self-reported. Current body composition was assessed by body mass index (BMI), waist circumference (WC) and percentage of body fat (BF%). Academic performance was assessed through schools records. RESULTS: Birth weight was related to all academic variables in boys, independent of potential confounders, including BMI; whereas WC, BMI and BF% were related to all academic performance indicators in both boys and girls, independent of potential confounders, including birth weight (all P < 0.05). In addition, the combined adverse effects of low birth weight and current overweight on academic performance were observed in both boys and girls for grade point average (GPA) indicator. Boys in the group with none adverse effect had significantly higher scores in GPA (score +0.535; 95% confidence interval, 0.082-0.989) than boys in the group of both adverse effects (P < 0.007); among girls, GPA score was higher in the group with none adverse effect than in the groups with one or two adverse effects (P for trend = 0.029). CONCLUSIONS: Neonatal and current body composition, both independently and combined, may influence academic performance in youth.