Maturitas 81 (2015) 1–2
Contents lists available at ScienceDirect
Maturitas journal homepage: www.elsevier.com/locate/maturitas
Guest Editorial
Obesity and mortality: Is childhood obesity shortening life expectancy?
There are many ways of assessing progress by human societies. For example, Karl Marx argued that social progress can be measured by the social position of the female sex. Against that measure, some human societies have made remarkable progress in the last two centuries but this benefit is spread very unevenly across the world. Human lifespan is another measure of societal progress which has been advancing steadily since the early 19th century. For most of the last 200 years, human life expectancy has been increasing at approximately 2 years per decade. Until the middle of the 20th century, most of this gain was due to reduced childhood mortality resulting from improved housing, food and water supplies and sanitation (driven by the growing economic and political power of rapidly expanding urban populations) which reduced the burden of, and risk of death from, childhood infections. This was augmented more latterly by public health interventions, notably inoculation, and by the widespread availability of antibiotics. Since then lifespan gains have come mainly from reduced adult mortality and, in particular, reduced mortality at older ages. However, as Martin Luther King has warned human progress is neither automatic nor inevitable and so it is with life expectancy. About 10 years ago, we began to hear that today’s children might not live as long as their parents. Progress appeared to be faltering or even being reversed. What had gone wrong? The finger of blame was pointed at the apparently epidemic rise in the prevalence of childhood obesity. Since 1980, prevalence rates of obesity in both developed and developing countries have been increasing and this rise is particularly marked for children and adolescents in developed countries [1]. In the USA, and in many other countries, more recent birth cohorts are becoming obese at progressively younger ages and are experiencing obesity for a greater proportion of their lifetime [2]. There is strong evidence that obesity in adulthood is associated with greater mortality from major age-related diseases [3]. Data for 2010 showed that overweight and obesity were estimated to cause 3.4 million deaths, equivalent to 4% of years of life lost [1]. In addition, childhood obesity is associated with greater mortality in adulthood [4]. However, it has been difficult to separate the effects of obesity in childhood per se from the effects of obesity in adulthood on mortality [5] not least because being obese as a child increases the risk of being an obese adult [6]. The molecular mechanisms responsible for the increased adult mortality of those who were fatter as children are poorly understood but are likely to involve the greater duration of exposure to the damaging effects of inflammation, oxidative stress/redox changes and metabolic stress http://dx.doi.org/10.1016/j.maturitas.2015.02.001 0378-5122/© 2015 Elsevier Ireland Ltd. All rights reserved.
which accompany obesity. Type 2 diabetes which used to be disease of middle-aged and older adults is now common among obese children and is both a consequence of excess adiposity and a cause of the molecular damage driving accelerated ageing. Body weight and body fatness can change markedly during childhood and adolescence so does it matter when children get fat? Investigation of repeated measurements of height and weight throughout childhood in nearly 5000 individuals born between 1934 and 1944 (the Helsinki Birth Cohort Study) showed that those children who had an increasing BMI trajectory had increased risk of premature mortality when adults compared with those with the average BMI trajectory – an adverse effect seen particularly in women [7]. This observation may be an example of the well-known Developmental Origins of Health and Disease (DOHaD) hypothesis showing that those born smaller (or thinner) who grow bigger (and fatter) than the average during childhood may be at greater risk of later life disease. Most low birth weight babies are born in Asia where rapid economic growth, combined with Westernisation of lifestyles, is driving up prevalence rates of both childhood and adult obesity. This double burden of impaired foetal growth followed by excess adiposity from childhood onwards means that Asia will suffer disproportionately from premature mortality associated with childhood obesity. A very recent analysis of primary care electronic health records evaluating changes in overweight and obesity among children in England over the period 1994–2013 revealed some encouraging news [8]. The steep rise in overweight and obesity seen in the decade from 1994 (8.1% annual increase) slowed markedly in the decade to 2013. Overweight and obesity prevalence appears to have stabilised in younger children but is still rising significantly (2.6% per year) among 11–15 year olds [8]. Importantly, there is no evidence that prevalence rates are falling in either gender or among any age group. Given the multitude of health and wellbeing problems which accompany obesity in childhood and, especially, in adolescence, intervening early in the life-course to prevent, or to reverse, obesity in children is a high profile public health priority. Not only does adiposity track from childhood to adulthood so do the major lifestyle behaviours (low physical activity and poor food consumption patterns) which cause obesity [9]. For this reason, changing eating habits to encourage greater intake of lower energy density foods (vegetables, fruits and low-fat, low-sugar starchy foods e.g. breads, pasta and rice) at the expense of fatty and sugary foods and sugar-rich drinks and establishing habits of greater
2
Guest Editorial / Maturitas 81 (2015) 1–2
physical activity will do much to reduce the risk of obesity and to improve the health and wellbeing of children. In addition, those leaner, more active children are much less likely to become overweight and obese adults and, as a consequence, to enjoy longer, healthier lives. However, the big challenge is to devise and to deliver cost-effective interventions which will produce sustained changes in lifestyle behaviours. Hamilton-Shield and Sharp have argued that we have no evidence from randomised controlled trials of effective, community-based, lifestyle intervention to address childhood obesity [10]. Future interventions are likely to operate at several levels from e.g. regulations on the composition or marketing of foods and snacks to children to interventions which attempt to change behaviours of individual children. Particularly for older children and for adolescents, digitally delivered interventions, based on behaviour change techniques which have been demonstrated to work in the target population and e.g. using social media, may be a route to acceptable, scalable and sustainable interventions to prevent or to manage obesity [11]. All of these will need more systematic collection of longitudinal data on anthropometry throughout childhood to support the development, implementation and evaluation of interventions at the national, regional, community or individual levels. Addressing obesity in childhood is unlikely to be a panacea and will need to be accompanied by interventions to improve lifestyle behaviours across the life-course if we are to maintain progress in extending human lifespan and to maximise healthy ageing. Competing interest The author has no financial or personal conflict of interest to disclose. Funding None.
Provenance and peer review Commissioned and not externally peer reviewed. References [1] Ng M, Fleming T, Robinson M, et al. Global, regional and national prevalence of obesity in children and adults during 1980–2013: a systematic analysis or the Global Burden of Disease Study 2013. Lancet 2014;384:766–81. [2] Lee JM, Pilli S, Gebremariam A, et al. Getting heavier younger: trajectories of obesity over the lifecourse. Int J Obes 2010;34:614–23. [3] Prospective Studies Collaboration. Body-mass index and cause-specific mortality in 900,000 adults: collaborative analyses of 57 prospective studies. Lancet 2009;373:1083–96. [4] Reilly JJ, Kelly J. Long-term impact of overweight and obesity in childhood and adolescence on morbidity and mortality in adulthood: systematic review. Int J Obes 2011;35:891–8. [5] Park MH, Falconer C, Viner RM, et al. The impact of childhood obesity on morbidity and mortality in adulthood: a systematic review. Obes Rev 2012;13:985–1000. [6] Singh AS, Mulder C, Twisk JWR, et al. Tracking of childhood overweight into adulthood: a systematic review of the literature. Obes Rev 2008;9:474–88. [7] von Bonsdorff MB, Törmäkangas T, Rantanen T, et al. Early life body mass trajectories and mortality in older age: Findings from the Helsinki Birth Cohort Study. Ann Med 2014 [PMID 25307361. Early online] [Epub ahead of print]. [8] van Jaarsveld CHM, Gulliford MC. Childhood obesity trends from primary care electronic health records in England between 1994 and 2013: population-based cohort study. Arch Dis Child 2015. PMID 25633067 [Epub ahead of print]. [9] Craigie AM, Lake AA, Kelly SA, et al. Tracking of obesity-related behaviours from childhood to adulthood: a systematic review. Maturitas 2011;70:266–84. [10] Hamilton-Shield J, Sharp D. Is the childhood obesity crisis over in England? Arch Dis Child 2015. PMID 25633068 [Epub ahead of print]. [11] Celis-Morales C, Lara J, Mathers JC. Personalising nutritional guidance for more effective behaviour change. Proc Nutr Soc 2014. PMID 25497396 [Epub ahead of print].
John C. Mathers Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
Contents lists available at ScienceDirect
Maturitas journal homepage: www.elsevier.com/locate/maturitas
Guest Editorial
Obesity and mortality: Is childhood obesity shortening life expectancy?
There are many ways of assessing progress by human societies. For example, Karl Marx argued that social progress can be measured by the social position of the female sex. Against that measure, some human societies have made remarkable progress in the last two centuries but this benefit is spread very unevenly across the world. Human lifespan is another measure of societal progress which has been advancing steadily since the early 19th century. For most of the last 200 years, human life expectancy has been increasing at approximately 2 years per decade. Until the middle of the 20th century, most of this gain was due to reduced childhood mortality resulting from improved housing, food and water supplies and sanitation (driven by the growing economic and political power of rapidly expanding urban populations) which reduced the burden of, and risk of death from, childhood infections. This was augmented more latterly by public health interventions, notably inoculation, and by the widespread availability of antibiotics. Since then lifespan gains have come mainly from reduced adult mortality and, in particular, reduced mortality at older ages. However, as Martin Luther King has warned human progress is neither automatic nor inevitable and so it is with life expectancy. About 10 years ago, we began to hear that today’s children might not live as long as their parents. Progress appeared to be faltering or even being reversed. What had gone wrong? The finger of blame was pointed at the apparently epidemic rise in the prevalence of childhood obesity. Since 1980, prevalence rates of obesity in both developed and developing countries have been increasing and this rise is particularly marked for children and adolescents in developed countries [1]. In the USA, and in many other countries, more recent birth cohorts are becoming obese at progressively younger ages and are experiencing obesity for a greater proportion of their lifetime [2]. There is strong evidence that obesity in adulthood is associated with greater mortality from major age-related diseases [3]. Data for 2010 showed that overweight and obesity were estimated to cause 3.4 million deaths, equivalent to 4% of years of life lost [1]. In addition, childhood obesity is associated with greater mortality in adulthood [4]. However, it has been difficult to separate the effects of obesity in childhood per se from the effects of obesity in adulthood on mortality [5] not least because being obese as a child increases the risk of being an obese adult [6]. The molecular mechanisms responsible for the increased adult mortality of those who were fatter as children are poorly understood but are likely to involve the greater duration of exposure to the damaging effects of inflammation, oxidative stress/redox changes and metabolic stress http://dx.doi.org/10.1016/j.maturitas.2015.02.001 0378-5122/© 2015 Elsevier Ireland Ltd. All rights reserved.
which accompany obesity. Type 2 diabetes which used to be disease of middle-aged and older adults is now common among obese children and is both a consequence of excess adiposity and a cause of the molecular damage driving accelerated ageing. Body weight and body fatness can change markedly during childhood and adolescence so does it matter when children get fat? Investigation of repeated measurements of height and weight throughout childhood in nearly 5000 individuals born between 1934 and 1944 (the Helsinki Birth Cohort Study) showed that those children who had an increasing BMI trajectory had increased risk of premature mortality when adults compared with those with the average BMI trajectory – an adverse effect seen particularly in women [7]. This observation may be an example of the well-known Developmental Origins of Health and Disease (DOHaD) hypothesis showing that those born smaller (or thinner) who grow bigger (and fatter) than the average during childhood may be at greater risk of later life disease. Most low birth weight babies are born in Asia where rapid economic growth, combined with Westernisation of lifestyles, is driving up prevalence rates of both childhood and adult obesity. This double burden of impaired foetal growth followed by excess adiposity from childhood onwards means that Asia will suffer disproportionately from premature mortality associated with childhood obesity. A very recent analysis of primary care electronic health records evaluating changes in overweight and obesity among children in England over the period 1994–2013 revealed some encouraging news [8]. The steep rise in overweight and obesity seen in the decade from 1994 (8.1% annual increase) slowed markedly in the decade to 2013. Overweight and obesity prevalence appears to have stabilised in younger children but is still rising significantly (2.6% per year) among 11–15 year olds [8]. Importantly, there is no evidence that prevalence rates are falling in either gender or among any age group. Given the multitude of health and wellbeing problems which accompany obesity in childhood and, especially, in adolescence, intervening early in the life-course to prevent, or to reverse, obesity in children is a high profile public health priority. Not only does adiposity track from childhood to adulthood so do the major lifestyle behaviours (low physical activity and poor food consumption patterns) which cause obesity [9]. For this reason, changing eating habits to encourage greater intake of lower energy density foods (vegetables, fruits and low-fat, low-sugar starchy foods e.g. breads, pasta and rice) at the expense of fatty and sugary foods and sugar-rich drinks and establishing habits of greater
2
Guest Editorial / Maturitas 81 (2015) 1–2
physical activity will do much to reduce the risk of obesity and to improve the health and wellbeing of children. In addition, those leaner, more active children are much less likely to become overweight and obese adults and, as a consequence, to enjoy longer, healthier lives. However, the big challenge is to devise and to deliver cost-effective interventions which will produce sustained changes in lifestyle behaviours. Hamilton-Shield and Sharp have argued that we have no evidence from randomised controlled trials of effective, community-based, lifestyle intervention to address childhood obesity [10]. Future interventions are likely to operate at several levels from e.g. regulations on the composition or marketing of foods and snacks to children to interventions which attempt to change behaviours of individual children. Particularly for older children and for adolescents, digitally delivered interventions, based on behaviour change techniques which have been demonstrated to work in the target population and e.g. using social media, may be a route to acceptable, scalable and sustainable interventions to prevent or to manage obesity [11]. All of these will need more systematic collection of longitudinal data on anthropometry throughout childhood to support the development, implementation and evaluation of interventions at the national, regional, community or individual levels. Addressing obesity in childhood is unlikely to be a panacea and will need to be accompanied by interventions to improve lifestyle behaviours across the life-course if we are to maintain progress in extending human lifespan and to maximise healthy ageing. Competing interest The author has no financial or personal conflict of interest to disclose. Funding None.
Provenance and peer review Commissioned and not externally peer reviewed. References [1] Ng M, Fleming T, Robinson M, et al. Global, regional and national prevalence of obesity in children and adults during 1980–2013: a systematic analysis or the Global Burden of Disease Study 2013. Lancet 2014;384:766–81. [2] Lee JM, Pilli S, Gebremariam A, et al. Getting heavier younger: trajectories of obesity over the lifecourse. Int J Obes 2010;34:614–23. [3] Prospective Studies Collaboration. Body-mass index and cause-specific mortality in 900,000 adults: collaborative analyses of 57 prospective studies. Lancet 2009;373:1083–96. [4] Reilly JJ, Kelly J. Long-term impact of overweight and obesity in childhood and adolescence on morbidity and mortality in adulthood: systematic review. Int J Obes 2011;35:891–8. [5] Park MH, Falconer C, Viner RM, et al. The impact of childhood obesity on morbidity and mortality in adulthood: a systematic review. Obes Rev 2012;13:985–1000. [6] Singh AS, Mulder C, Twisk JWR, et al. Tracking of childhood overweight into adulthood: a systematic review of the literature. Obes Rev 2008;9:474–88. [7] von Bonsdorff MB, Törmäkangas T, Rantanen T, et al. Early life body mass trajectories and mortality in older age: Findings from the Helsinki Birth Cohort Study. Ann Med 2014 [PMID 25307361. Early online] [Epub ahead of print]. [8] van Jaarsveld CHM, Gulliford MC. Childhood obesity trends from primary care electronic health records in England between 1994 and 2013: population-based cohort study. Arch Dis Child 2015. PMID 25633067 [Epub ahead of print]. [9] Craigie AM, Lake AA, Kelly SA, et al. Tracking of obesity-related behaviours from childhood to adulthood: a systematic review. Maturitas 2011;70:266–84. [10] Hamilton-Shield J, Sharp D. Is the childhood obesity crisis over in England? Arch Dis Child 2015. PMID 25633068 [Epub ahead of print]. [11] Celis-Morales C, Lara J, Mathers JC. Personalising nutritional guidance for more effective behaviour change. Proc Nutr Soc 2014. PMID 25497396 [Epub ahead of print].
John C. Mathers Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
