ORCP-405; No. of Pages 5
ARTICLE IN PRESS
Obesity Research & Clinical Practice (2015) xxx, xxx.e1—xxx.e5
SHORT REPORT
Physical inactivity among older adults: Implications for life expectancy among non-overweight and overweight or obese individuals Ngaire Coombs a,b,c,∗, Emmanuel Stamatakis a,b,d,e,f, I-Min Lee g a
Department of Epidemiology and Public Health, University College London, London, UK b PARG (Physical Activity Research Group), Population Health Domain, University College London, London, UK c Department of Social Statistics and Demography, University of Southampton, Southampton, UK d Prevention Research Collaboration, School of Public Health, University of Sydney, Australia e Charles Perkins Centre, University of Sydney, Australia f Exercise Science Discipline, Faculty of Health Sciences, University of Sydney, Australia g Division of Preventive Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, USA Received 25 September 2014; accepted 11 November 2014
KEYWORDS Life expectancy; Population attributable fraction;
Summary This study investigates to what extent physical inactivity in older age is associated with reduced life expectancy among non-overweight and overweight/obese individuals. Data from 20,203 respondents aged ≥60 years were drawn from the Health Survey for England and Scottish Health Surveys (1994—2008) and 5year all-cause mortality linkage. Population attributable fractions were calculated to estimate years of life lost due to physical inactivity. Physical inactivity was defined
∗
Corresponding author at: Department of Social Statistics and Demography, University of Southampton, Southampton, Hampshire SO17 1BJ, UK. E-mail address: [email protected] (N. Coombs). http://dx.doi.org/10.1016/j.orcp.2014.11.004 1871-403X/© 2014 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Coombs N, et al. Physical inactivity among older adults: Implications for life expectancy among non-overweight and overweight or obese individuals. Obes Res Clin Pract (2015), http://dx.doi.org/10.1016/j.orcp.2014.11.004
ORCP-405; No. of Pages 5
ARTICLE IN PRESS
xxx.e2
N. Coombs et al.
Obesity; Older adults; Physical activity
as not meeting the current UK physical activity guidelines for older adults. Not meeting physical activity guidelines was associated with reduced life expectancy that is larger among non-overweight individuals than among overweight/obese. © 2014 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Introduction
The physical activity questionnaire has been described previously in detail [10]. In brief, questions enquired about frequency, duration, and intensity of heavy domestic physical activity, walking, cycling and a broad range of recreational sports and exercises in the last 4 weeks. This questionnaire has been tested against accelerometry-measured physical activity and shown to be valid [11]. Using existing methodology [12], types and intensities of physical activity were converted into metabolic equivalents (METs). A MET of 3 < 6 was considered moderate, and 6+ vigorous intensity physical activity. Physically active and inactive categories were determined from the UK 2011 Chief Medical Officers PA recommendations for older adults [13]. Physically active was defined as moderate intensity PA for at least 150 min a week or vigorous intensity PA for at least 75 min a week, or a combination of the two. Trained interviewers collected data on general health (5 point scale) longstanding illness, ethnicity, and cigarette smoking status. Height and weight were measured using Chasmors stadiometers and Tanita electronic digital scales, respectively. BMI was calculated from weight and height in the standard way (kg/m2 ). BMI values less than 25 were classified as not overweight, values greater or equal to 25 as overweight/obese [5]. We did not include separate categories for underweight and obese groups due to small numbers of participants in these categories. Cox-proportional hazard models were run to obtain hazard ratios for mortality from physical inactivity, adjusting for age and sex, and additionally for general health, longstanding illness, ethnicity, and smoking status. Sex-specific 5 year abridged period life tables (age 60 years and older) were generated using mortality rates for Great Britain in 1998—2000 [14]. Because life expectancy is different for non-overweight and overweight/obese individuals separate life tables were compiled for non-overweight and overweight/obese BMI subgroups. This was achieved by calculating the age-specific relative risk of mortality for overweight/obese compared to nonoverweight individuals (controlling for longstanding illness, general health, and smoking status), and adjusting the age-specific mortality rate in the
Physical inactivity is a well-established risk factor for chronic diseases and premature mortality [1] and is associated with reduced life expectancy [2]. Despite the established importance of physical activity (PA) for health, in 2012 33% of men and 45% of women living in England were inactive according to current PA guidelines. Physical inactivity is particularly pronounced at older ages: by age 65—74 42% of men and 48% of women were inactive, increasing to 57% and 79% for those aged 75—84 [3]. Overweight and obesity are also risk factors for chronic disease and premature mortality, and PA is associated with reduced adiposity [4], although associations of body mass index (BMI)-defined overweight with mortality is a subject of controversy [5]. Being physically active may be more important for health outcomes than having a low BMI as some studies show that active obese individuals have lower all-cause mortality risk than inactive non-obese individuals [6]; however, other studies report that those with high BMI but good levels of PA have higher all-cause mortality than those with low BMI and poor levels of PA [7]. Physical inactivity and BMI are competing, interlinked risk factors for premature mortality. While it is well-established that regular PA is beneficial for longevity [2], there is little information on how the benefits of PA differ by BMI status (which in itself influences longevity). To address this aim we examined longevity benefits of PA in different BMI subgroups using a series of large nationally representative population-based samples from England and Scotland and associated mortality linkage.
Methods Details of the sample design and selection can be found elsewhere [8,9]. In brief, participants were drawn from the nationally representative Health Survey for England and the Scottish Health Survey, which are conducted annually and every 5 years, respectively. For this study 9 surveys between 1994 and 2008 were linked to 5-year mortality follow up for respondents aged 60 and over (N = 20,203, 2,671 decedents).
Please cite this article in press as: Coombs N, et al. Physical inactivity among older adults: Implications for life expectancy among non-overweight and overweight or obese individuals. Obes Res Clin Pract (2015), http://dx.doi.org/10.1016/j.orcp.2014.11.004
ARTICLE IN PRESS
ORCP-405; No. of Pages 5
Physical inactivity, BMI and life expectancy Table 1
xxx.e3
Sample characteristics of selected variables by BMI status.
Continuous variables
Age (years)
Non-overweight (BMI < 25)
Overweight or obese (BMI ≥ 25)
M
SD
N
M
SD
N
70.6
(7.8)
6,093
69.2
(6.9)
14,110
p*
ARTICLE IN PRESS
Obesity Research & Clinical Practice (2015) xxx, xxx.e1—xxx.e5
SHORT REPORT
Physical inactivity among older adults: Implications for life expectancy among non-overweight and overweight or obese individuals Ngaire Coombs a,b,c,∗, Emmanuel Stamatakis a,b,d,e,f, I-Min Lee g a
Department of Epidemiology and Public Health, University College London, London, UK b PARG (Physical Activity Research Group), Population Health Domain, University College London, London, UK c Department of Social Statistics and Demography, University of Southampton, Southampton, UK d Prevention Research Collaboration, School of Public Health, University of Sydney, Australia e Charles Perkins Centre, University of Sydney, Australia f Exercise Science Discipline, Faculty of Health Sciences, University of Sydney, Australia g Division of Preventive Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, USA Received 25 September 2014; accepted 11 November 2014
KEYWORDS Life expectancy; Population attributable fraction;
Summary This study investigates to what extent physical inactivity in older age is associated with reduced life expectancy among non-overweight and overweight/obese individuals. Data from 20,203 respondents aged ≥60 years were drawn from the Health Survey for England and Scottish Health Surveys (1994—2008) and 5year all-cause mortality linkage. Population attributable fractions were calculated to estimate years of life lost due to physical inactivity. Physical inactivity was defined
∗
Corresponding author at: Department of Social Statistics and Demography, University of Southampton, Southampton, Hampshire SO17 1BJ, UK. E-mail address: [email protected] (N. Coombs). http://dx.doi.org/10.1016/j.orcp.2014.11.004 1871-403X/© 2014 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Coombs N, et al. Physical inactivity among older adults: Implications for life expectancy among non-overweight and overweight or obese individuals. Obes Res Clin Pract (2015), http://dx.doi.org/10.1016/j.orcp.2014.11.004
ORCP-405; No. of Pages 5
ARTICLE IN PRESS
xxx.e2
N. Coombs et al.
Obesity; Older adults; Physical activity
as not meeting the current UK physical activity guidelines for older adults. Not meeting physical activity guidelines was associated with reduced life expectancy that is larger among non-overweight individuals than among overweight/obese. © 2014 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Introduction
The physical activity questionnaire has been described previously in detail [10]. In brief, questions enquired about frequency, duration, and intensity of heavy domestic physical activity, walking, cycling and a broad range of recreational sports and exercises in the last 4 weeks. This questionnaire has been tested against accelerometry-measured physical activity and shown to be valid [11]. Using existing methodology [12], types and intensities of physical activity were converted into metabolic equivalents (METs). A MET of 3 < 6 was considered moderate, and 6+ vigorous intensity physical activity. Physically active and inactive categories were determined from the UK 2011 Chief Medical Officers PA recommendations for older adults [13]. Physically active was defined as moderate intensity PA for at least 150 min a week or vigorous intensity PA for at least 75 min a week, or a combination of the two. Trained interviewers collected data on general health (5 point scale) longstanding illness, ethnicity, and cigarette smoking status. Height and weight were measured using Chasmors stadiometers and Tanita electronic digital scales, respectively. BMI was calculated from weight and height in the standard way (kg/m2 ). BMI values less than 25 were classified as not overweight, values greater or equal to 25 as overweight/obese [5]. We did not include separate categories for underweight and obese groups due to small numbers of participants in these categories. Cox-proportional hazard models were run to obtain hazard ratios for mortality from physical inactivity, adjusting for age and sex, and additionally for general health, longstanding illness, ethnicity, and smoking status. Sex-specific 5 year abridged period life tables (age 60 years and older) were generated using mortality rates for Great Britain in 1998—2000 [14]. Because life expectancy is different for non-overweight and overweight/obese individuals separate life tables were compiled for non-overweight and overweight/obese BMI subgroups. This was achieved by calculating the age-specific relative risk of mortality for overweight/obese compared to nonoverweight individuals (controlling for longstanding illness, general health, and smoking status), and adjusting the age-specific mortality rate in the
Physical inactivity is a well-established risk factor for chronic diseases and premature mortality [1] and is associated with reduced life expectancy [2]. Despite the established importance of physical activity (PA) for health, in 2012 33% of men and 45% of women living in England were inactive according to current PA guidelines. Physical inactivity is particularly pronounced at older ages: by age 65—74 42% of men and 48% of women were inactive, increasing to 57% and 79% for those aged 75—84 [3]. Overweight and obesity are also risk factors for chronic disease and premature mortality, and PA is associated with reduced adiposity [4], although associations of body mass index (BMI)-defined overweight with mortality is a subject of controversy [5]. Being physically active may be more important for health outcomes than having a low BMI as some studies show that active obese individuals have lower all-cause mortality risk than inactive non-obese individuals [6]; however, other studies report that those with high BMI but good levels of PA have higher all-cause mortality than those with low BMI and poor levels of PA [7]. Physical inactivity and BMI are competing, interlinked risk factors for premature mortality. While it is well-established that regular PA is beneficial for longevity [2], there is little information on how the benefits of PA differ by BMI status (which in itself influences longevity). To address this aim we examined longevity benefits of PA in different BMI subgroups using a series of large nationally representative population-based samples from England and Scotland and associated mortality linkage.
Methods Details of the sample design and selection can be found elsewhere [8,9]. In brief, participants were drawn from the nationally representative Health Survey for England and the Scottish Health Survey, which are conducted annually and every 5 years, respectively. For this study 9 surveys between 1994 and 2008 were linked to 5-year mortality follow up for respondents aged 60 and over (N = 20,203, 2,671 decedents).
Please cite this article in press as: Coombs N, et al. Physical inactivity among older adults: Implications for life expectancy among non-overweight and overweight or obese individuals. Obes Res Clin Pract (2015), http://dx.doi.org/10.1016/j.orcp.2014.11.004
ARTICLE IN PRESS
ORCP-405; No. of Pages 5
Physical inactivity, BMI and life expectancy Table 1
xxx.e3
Sample characteristics of selected variables by BMI status.
Continuous variables
Age (years)
Non-overweight (BMI < 25)
Overweight or obese (BMI ≥ 25)
M
SD
N
M
SD
N
70.6
(7.8)
6,093
69.2
(6.9)
14,110
p*
