Introduction
Obesity is a health concern in both developed and developing countries. Numerous studies have documented an increase in the prevalence of obesity worldwide, a trend that has been described as an ‘epidemic’. Increases in the prevalence of obesity have been observed in men and women, in all age groups, in all major ethnic groups, and at all educational levels. According to the World Health Organization (WHO), obesity prevalence has doubled since 1980.1 Some authors argue that up to one-third of the life expectancy gains over time attributable to public health achievements, such as reductions in smoking, are counteracted by the simultaneous increase in obesity prevalence.Reference Neovius, Rasmussen, Sundstrom and Neovius2.Reference Stewart, Cutler and Rosen3 Among older adults, obesity has been related to higher rates of disability and poor overall health.Reference Zamboni, Mazzali, Zoico, Harris, Meigs, Di Francesco, Fantin, Bissoli and Bosello4 This is especially relevant given the expected worldwide growth of older adult populations.
We searched Medline, PubMed, EMBASE and World of Science databases and websites for the World Health Organization, and for major longitudinal studies on ageing such as the English Longitudinal Study on Ageing (ELSA) (http://www.esds.ac.uk/longitudinal/access/elsa/), the Survey of Health, Ageing and Retirement in Europe (SHARE) (http://www.share-project.org/), the Health and Retirement Study (HRS) (http://hrsonline.isr.umich.edu/), and The Health, Well-Being, and Ageing Survey (SABE) (http://www.ssc.wisc.edu/sabe). We did not limit the search by type of study given the complexity of the topics addressed; however, we did limit the search to manuscripts published in core clinical and epidemiological journals between 1991 and 2011, given the focus of the review. Our initial search terms included ‘obesity’, ‘prevalence’, ‘trends’, ‘older adults’ and ‘epidemiology’. We went on to conduct several further searches to find articles related to obesity and disability and obesity and chronic diseases for each of the sub-sections covered in this article.
Epidemiology of obesity around the world
Comparisons between regions around the world indicate a wide variation in prevalence of obesity. Despite these regional differences, over time the prevalence of obesity has increased worldwide.1Table 1 summarizes the prevalence of obesity according to studies published in the last two decades using information from three regions in the world: North America (USA and Canada), Latin America and Europe.
Table 1. Summary of literature review of studies reporting prevalence of obesity around the world in the past two decades
CNPHS, Canadian National Population Health Survey; NHANES, National Health and Nutrition Examination Survey (USA); ELSA, English Longitudinal Study of Ageing; SHARE, Survey of Health, Ageing and Retirement in Europe; SABE, Health, Well-being and Ageing Survey (Latin America and the Caribbean); MHAS, Mexican Health and Ageing Study. BLSA, Baltimore Longitudinal Study of Aging; EUROASPIRE, Europe Action on Secondary and Primary Interventions to Reduce Events; WHO, World Health Organization; BMI, body mass index; WHO cut-off points, BMI ≥30 kg/m2.
In the United States, studies using data from the National Health and Nutrition Examination Survey (NHANES) report increasing trends in obesity over time.Reference Bleich, Wang, Wang and Gortmaker5–Reference Ford, Li, Zhao and Tsai10 Ford and colleagues reported an increase in the prevalence of obesity from 11.1% in the 1970s to 19.3% in the early 2000s.Reference Ford, Li, Zhao, Pearson and Capewell9 The most recent data from NHANES report obesity prevalence to be approximately 32% for men and 36% for women.Reference Flegal, Carroll, Ogden and Curtin8, Reference Ford, Li, Zhao and Tsai10 The difference between men and women is not statistically significant based on the overlapping confidence intervals. Nevertheless, the trend over time has continued to increase for men, while for women it seems to be stabilizing.Reference Flegal, Carroll, Ogden and Curtin8, Reference Stenholm, Simonsick and Ferrucci11 Race/ethnic differences are also reported in the increasing obesity trends, with African-Americans having the highest rates, followed by Hispanics.Reference Flegal, Carroll, Ogden and Curtin8
Obesity in Canada is lower. The overall prevalence of obesity in the mid-1990s was reported at 12.8%,Reference Kaplan, Huguet, Newsom, McFarland and Lindsay12 half that reported in the USA using data from the NHANES study in a similar time period (Table 1). A steady rise in the obesity trends is observed in Canada as well, with obesity rates of 8.1% for men in the 1970s increasing to 13.4% in the 1990s, and rates of 12.7% rising to 15.4% in women.Reference Torrance, Hooper and Reeder13 MacDonald and colleagues, using the cut-off point of 27 kg/m2 for obesity, found obesity rate of 35% for men and 27% for women in ten provinces from Canada.Reference Macdonald, Reeder, Chen and Despres14 The lower cut-off point explains the large difference in the prevalence between this and the other Canadian studies (Table 1). Nevertheless, we cannot determine why the prevalence rate is higher in men than in women, in contrast to studies in North America. Ethnic differences are also observed in Canada, with Aboriginals reporting higher rates of obesity.Reference Bruce, Riediger, Zacharias and Young15, Reference Lix, Bruce, Sarkar and Young16
The few studies available on prevalence of obesity in Latin America and the Caribbean in older adults also report an increase over time. A large variation between countries is also observed.Reference Al Snih, Ray and Markides17–Reference Ruiz-Arregui, Castillo-Martinez, Orea-Tejeda, Mejia-Arango and Miguel-Jaimes19 Using data from The Health, Well-Being and Ageing Survey (SABE), the prevalence of category I obesity (BMI of 30 to <35 kg/m2) for men and women combined, ranged between 10.4% in Havana to 22.9% in Santiago; the prevalence of category II and extreme obesity (BMI ≥ 35 kg/m2) ranged from 2.9% in Havana to 15.7% in Montevideo.Reference Al Snih, Ray and Markides17 Thus obesity of any category ranged between 13.3 and 38.6% in the SABE study (Table 1). The two remaining studies summarized in Table 1 on Latin America were conducted only in Brazil and Mexico. In Brazil the prevalence of obesity seemed to reach a plateau in the early 2000s for women, while for men the trend continued to increase.Reference Monteiro, Conde and Popkin18 The prevalence reported in the single country studies falls in the range reported in the SABE study (Table 1).
In Europe, both cross-sectional and longitudinal studies report a large variation in the prevalence of obesity between countries. Using data from the Europe Action on Secondary and Primary Intervention through Intervention to Reduce Events (EUROASPIRE) surveys, the average prevalence of obesity increased from 25% in EUROASPIRE I to 38% in EUROASPIRE III.Reference Kotseva, Wood, De, De, Pyorala and Keil20 Studies using data from the Survey of Health, Ageing and Retirement in Europe (SHARE) and the English Longitudinal Study of Ageing (ELSA) reported average prevalence of obesity for men of 16.2%, and 17.8% for women.Reference Andreyeva, Michaud and van Soest21 Nevertheless the variation observed ranges between 12.8% for men in Sweden to 20.2% for men in Spain, and between 12.3% for women in Switzerland to 21.9% for women in Greece (Table 1). Studies using data from only one country also reported a difference in the prevalence of obesity between men and women and an increasing trend in the prevalence of obesity over time.Reference Charles, Eschwege and Basdevant22–Reference Gomez-Cabello, Pedrero-Chamizo, Olivares, Luzardo, Juez-Bengoechea and Mata27 In most countries the prevalence of obesity is higher for women (Table 1).
Cross-sectional studies comparing the USA with Europe showed that obesity rates in the USA were higher for both men and women (Table 1). In 2004, the prevalence of obesity for the USA was reported at 30.7% for men compared with 17.6% in Europe, and 37.9% in women compared with 24.2%, respectively.Reference Michaud, van Soest and Andreyeva28 A large variability is noted again between obesity rates in the different European countries. However, no country reaches the exceedingly high obesity rates of the USA. One last study examined obesity rates among Inuit people in Canada, Alaska and Greenland and reported no significant differences between countries, with an overall prevalence of obesity of 15.8% for Inuit men and 25.5% for Inuit women.Reference Young, Bjerregaard, Dewailly, Risica, Jorgensen and Ebbesson29
Finally, Stewart and colleagues used data from the NHANES study to predict obesity rates in 2020 and estimate its impact on mortality.Reference Stewart, Cutler and Rosen3 Their projections showed that life expectancy is decreased by almost 1 year in the USA for a representative 18-year-old person, assuming trends in smoking continue to decrease and trends in body mass index (BMI) continue to increase at the same rate observed between 1973 and 2005. Additionally, the projection shows that the overall prevalence of obesity for adults in the USA will be 45% by the year 2020.Reference Stewart, Cutler and Rosen3
We did not include Asia, Africa or Oceania as regions in Table 1 because of the limited number of studies available on the epidemiology of obesity in older adults in these continents. Additionally, a large variability in the prevalence of obesity has been reported in the literature on Asian older adults. However, to include all major regions in the world we analysed two documents that analyse obesity in Asia and Australia. Based on a report by the WHO, the major difficulty with accurately examining obesity among Asians is the large variation in cultural and economic conditions of Asian populations and the fact that current WHO cut-off points for obesity seem to provide an erroneous estimate based on higher prevalence of adverse events at lower BMI values. This report by the WHO proposes that the cut-off point for obesity among Asian adults should be 25 kg/m2.30
The WHO report on Asia summarizes some studies that have looked at epidemiology of obesity. Most data on obesity in Asia come from single country studies or from countries where a large portion of the population is of Asian origin, like the island of Mauritius. Obesity trends are rapidly rising in all Asian nations. Obesity rates range between less than 1% in rural populations in countries like China, to around 9% in urban areas of Malaysia. A large variation by gender and ethnicity is observed in several countries including Malaysia and China. In summary, the data from Asian countries reports much lower obesity rates compared with other regions. The WHO, however, strongly advocates for a new definition of obesity with different cut-off points based on the trends in obesity rates and the increase in the prevalence of obesity-associated complications such as cardiovascular diseases.
In Australia, analysis of trends from cross-sectional surveys conducted since the 1980s were summarized by the Australian Institute of Health and Welfare in a bulletin published in 2004.Reference Bennet, Magnus and Gibson31 Similar to what has been reported in other continents, the rates of obesity among older adults has increased over time. Between the 1980s and the early 2000s an increase in prevalence of obesity was observed from 11 to 23% in adults over 65.Reference Bennet, Magnus and Gibson31 The most recent reports show that between 25 and 30% of adults approaching retirement in Australia are obese.
In summary, obesity has increased noticeably in all continents among older adults. Large variations between countries, race/ethnic groups and genders are observed. Despite these variations, public health implications need to be carefully analysed and addressed to prevent obesity, disability and decreased quality of life for older adults around the world in the near future.
Obesity and disability
Disability is a broad term that can be defined in many different ways. Lack of a single definition and availability of several validated tools to measure different types of disability make cross-study comparisons on disability difficult. Nevertheless, the ample literature showing that disability increases the risk of mortality and institutionalization and affects quality of life in older age make disability a concept that must be carefully analysed and better understood.Reference Fried, Ferrucci, Darer, Williamson and Anderson32–Reference Verbrugge, Reoma and Gruber-Baldini35 Conditions that increase the risk of disability are therefore highly important.
Table 2 summarizes relevant studies that analyse the relationship between obesity and disability. Obesity is not measured consistently although all studies use either BMI, waist circumference or body composition to define obesity. Similarly, the definition of disability varies between the different studies. The first studies listed are longitudinal studies. They are consistent in showing that, over time, the presence of obesity increases the risk of becoming disabled.Reference Lang, Llewellyn, Alexander and Melzer25, Reference Al Snih, Ottenbacher, Markides, Kuo, Eschbach and Goodwin36–Reference Wee, Huskey, Ngo, Fowler-Brown, Leveille, Mittlemen and McCarthy43 Nevertheless, of the nine longitudinal studies listed, seven studies use activities of daily living (ADL) to define disability.Reference Lang, Llewellyn, Alexander and Melzer25, Reference Al Snih, Ottenbacher, Markides, Kuo, Eschbach and Goodwin36, Reference Reynolds, Saito and Crimmins38, Reference Sturm, Ringel and Andreyeva39, Reference Walter, Kunst, Mackenbach, Hofman and Tiemeier41–Reference Wee, Huskey, Ngo, Fowler-Brown, Leveille, Mittlemen and McCarthy43 Five of the seven studies use the same six activities (walking across a room, bathing, eating, dressing, toileting and transferring in and out of bed) and define disability as difficulty performing one or more activities.Reference Lang, Llewellyn, Alexander and Melzer25, Reference Al Snih, Ottenbacher, Markides, Kuo, Eschbach and Goodwin36, Reference Reynolds, Saito and Crimmins38, Reference Sturm, Ringel and Andreyeva39, Reference Wee, Huskey, Ngo, Fowler-Brown, Leveille, Mittlemen and McCarthy43 From these studies we can conclude that obesity is an independent risk factor for developing ADL disability over time. The remaining studies use upper and lower body function and work-related disability. Each study concludes that obesity increases the risk of the defined disability.Reference Ferraro, Su, Gretebeck, Black and Badylak37, Reference Visscher, Rissanen, Seidell, Heliovaara, Knekt, Reunanen and Aromaa40 The studies by Reynolds et al. and Walter et al. also conclude that obesity hampers the probability of recovery from disability in older adults.Reference Reynolds, Saito and Crimmins38, Reference Walter, Kunst, Mackenbach, Hofman and Tiemeier41 In some of the longitudinal studies, the effect of obesity on disability was larger for women compared with men (Table 2).
Table 2. Summary of literature review of studies analysing the relationship between obesity and disability
CCHS, Canadian Community Health Survey; NPHS, National Population Health Survey in Canada; ADL, activities of daily living; IADL, instrumental activities of daily living; DXA, dual energy X-ray absorptiometry; ELSA, English Longitudinal Study on Ageing; HAQ-DI, Health Assessment Questionnaire Disability Index; HRS, Health Retirement Study; SABE, The Health, Well-Being and Ageing Survey; PASE, The Physical Activity Scale for the Elderly; WC, waist circumference; SPBB, Short Physical Performance Battery; WHO, World Health Organization; BMI, body mass index; WHO cut-off points, BMI ≥30 kg/m2.
Following the longitudinal studies, cross-sectional studies analysing the relationship between obesity and disability are listed (Table 2). Similar to the longitudinal studies, disability is defined in different ways. Of the 11 cross-sectional studies included, seven use ADL exclusively or in combination with other functionality measures to define disability.Reference Al Snih, Graham, Kuo, Goodwin, Markides and Ottenbacher44–Reference Zoico, Di Francesco, Guralnik, Mazzali, Bortolani, Guariento, Sergi, Bosello and Zamboni50 Three studies also use instrumental activities of daily living (IADL) to define disability.Reference Berraho, Nejjari, Raherison, El, Tachfouti, Serhier, Dartigues and Barberger-Gateau46, Reference Chen and Guo48, Reference Zoico, Di Francesco, Guralnik, Mazzali, Bortolani, Guariento, Sergi, Bosello and Zamboni50 The remaining studies use either physical function or mobility disability to define disability.Reference Pedersen, Ovesen, Schroll, Avlund and Era51–Reference Woo, Leung and Kwok54 All studies conclude that obesity is related to increased disability regardless of how it is measured. Some of the studies analyse the relationship between obesity and muscle strength and suggest that, despite the deleterious effects of obesity on muscle function, additional pathways need to be analysed to understand the pathophysiology behind the onset of disability in older obese adults.Reference Zoico, Di Francesco, Guralnik, Mazzali, Bortolani, Guariento, Sergi, Bosello and Zamboni50–Reference Woo, Leung and Kwok54
Several studies report that the relationship between weight or BMI and disability has a ‘U’ or a ‘J’ shape, meaning that not only obesity but underweight older adults have increased risk of disability.Reference Al Snih, Ottenbacher, Markides, Kuo, Eschbach and Goodwin36, Reference Alley and Chang45, Reference Chen and Guo48 Normal weight and some overweight older adults seem to have the lowest risk of disability of all weight or BMI groups. This has important implications for prevention and treatment schemes, since losing too much weight can be detrimental for older adults as well.
In summary, obesity is related to increased risk of disability among older adult populations. Obesity also seems to affect recovery from disability over time. Obesity not only affects functional status but it also affects mobility. Policy makers and healthcare providers need to keep this relationship in mind, and design obesity prevention and obesity management programmes that can improve functional status in older adults and protect them from becoming disabled, with resultant poor quality of life.
Implications of obesity on chronic diseases
Despite the widely know deleterious effects of obesity on overall health, obesity in older age has to be analysed with caution. Obesity significantly increases the risk of death among older adults. Nevertheless, the relationship between BMI and mortality is unique in the older adult population because very low BMI values are related to the highest mortality risk; this risk decreases as BMI increases to normal and overweight values and then mortality risk increases again, with a sharp increase in BMI values greater than 35 kg/m2.Reference Al Snih, Ottenbacher, Markides, Kuo, Eschbach and Goodwin36, Reference Auyeung, Lee, Leung, Kwok, Leung and Woo55, Reference Kapoor and Heidenreich56 Additionally, weight loss has been reported as a risk factor for adverse events in some older adults including fractures, falls and mortality.Reference Amador, Al, Markides and Goodwin57, Reference Locher, Roth, Ritchie, Cox, Sawyer, Bodner and Allman58 Despite this, healthcare costs for older obese adults are higher than for older adults with normal weight.Reference Daviglus, Liu, Yan, Pirzada, Manheim, Manning, Garside, Wang, Dyer, Greenland and Stamler59, Reference Raebel, Malone, Conner, Xu, Porter and Lanty60 Similarly, disability rates and complications from obesity have been widely reported among the older adult population.Reference Nafiu, Kheterpal, Moulding, Picton, Tremper, Campbell, Eliason and Stanley61–Reference Zacharias, Schwann, Riordan, Durham, Shah and Habib63 We reviewed the literature and have summarized the implications of obesity on different diseases in the older adult population.
Obesity and cardiovascular disease
Obesity is an independent risk factor for development of heart failure, and acute events like myocardial infarctions and stroke in older adults.Reference Caterson, Hubbard, Bray, Grunstein, Hansen, Hong, Labarthe, Seidell and Smith64, Reference Kurth, Gaziano, Berger, Kase, Rexrode, Cook, Buring and Manson65 Obesity increases the risk of hypertension and affects overall response to anti-hypertensive medications.Reference Hayashi, Boyko, Leonetti, McNeely, Newell-Morris, Kahn and Fujimoto66–Reference Wang, Larson, Levy, Benjamin, Leip, Wilson and Vasan68 A ‘U’-shaped relationship between BMI and hypertension has been reported.Reference Uretsky, Messerli, Bangalore, Champion, Cooper-Dehoff, Zhou and Pepine69 Two major causes have emerged as explanatory causes for cardiovascular disease resulting from obesity: anatomical and physiological alterations. Anatomical alterations are explained because obesity affects the architecture and physiology of the cardiovascular system. Obesity causes atrial and ventricular enlargement and plaque formation in the vessels.Reference Al Suwaidi, Higano, Hamasaki, Holmes and Lerman70–Reference Russo, Jin, Homma, Rundek, Elkind, Sacco and Di Tullio72 These changes not only affect cardiovascular function, but also increase the risk of developing potentially lethal conditions like atrial fibrillation and abdominal aortic aneurysms.Reference Dublin, French, Glazer, Wiggins, Lumley, Psaty, Smith and Heckbert73, Reference Golledge, Clancy, Jamrozik and Norman74
Obesity triggers metabolic dysregulation and inflammation.Reference Zoico, Di Francesco, Guralnik, Mazzali, Bortolani, Guariento, Sergi, Bosello and Zamboni50, Reference Bahrami, Bluemke, Kronmal, Bertoni, Lloyd-Jones, Shahar, Szklo and Lima75, Reference Fontana, Eagon, Trujillo, Scherer and Klein76 Decreased levels of natriuretic peptide, a peptide that protects against acute events like myocardial infarctions, have been reported.Reference Wang, Larson, Levy, Benjamin, Leip, Wilson and Vasan68, Reference Lorgis, Cottin, Danchin, Mock, Sicard, Buffet, L'huillier, Richard, Beer, Touzery, Gambert and Zeller77 Other physiological alterations include increased levels of inflammatory markers (interleukin-6, C-reactive protein and tumour necrosis factor) that affect the body's response to physiological changes and put an additional burden on the cardiovascular system.Reference Fontana, Eagon, Trujillo, Scherer and Klein76 Increased adiposity enhances insulin resistance and therefore the risk for adverse cardiovascular events overall.Reference Zoico, Di Francesco, Guralnik, Mazzali, Bortolani, Guariento, Sergi, Bosello and Zamboni50, Reference Karter, Mayer-Davis, Selby, D'Agostino, Haffner, Sholinsky, Bergman, Saad and Hamman78
Obesity, diabetes and the metabolic syndrome
Obesity, diabetes and the metabolic syndrome are closely related. Obesity and diabetes are distinct clinical conditions that occur independently despite sharing some pathophysiological pathways. The metabolic syndrome is also independent from obesity and diabetes. It is a collection of risk factors that cause damage to the cardiovascular system, increasing the risk of heart attack, stroke and other cardiovascular diseases. Increased body fat and increased blood sugar are two of the five components of the metabolic syndrome.Reference Smith, Jr, Clark, Cooper, Daniels, Kumanyika, Ofili, Quinones, Sanchez, Saunders and Tiukinhoy79, Reference Vega80
Unlike the relationship between obesity and mortality in older adults, the relationship between obesity, diabetes and the metabolic syndrome is very similar in older adults compared with younger adults. A large body of evidence has shown that obesity increases the risk of developing diabetes and the metabolic syndrome.Reference Vega80, Reference Goodpaster, Krishnaswami, Harris, Katsiaras, Kritchevsky, Simonsick, Nevitt, Holvoet and Newman81 There is also evidence that obesity, diabetes and the metabolic syndrome are independent risk factors for cardiovascular disease.Reference Vega80 Increased oxidative stress in fatty tissue of obese individuals has been proposed as a pathogenic mechanism leading to the metabolic syndrome.Reference Furukawa, Fujita, Shimabukuro, Iwaki, Yamada, Nakajima, Nakayama, Makishima, Matsuda and Shimomura82 Additionally, severity of obesity (determined by National Heart Lung and Blood Institute Task Force categories: class 1, class 2 and class 3) is associated with an increasing trend in risk of development of diabetes and the metabolic syndrome.Reference Ruland, Hung, Richardson, Misra and Gorelick83 It has been reported that this relationship between obesity, diabetes and the metabolic syndrome is especially important among minority populations in developed countries given the higher rates of obesity compared with other population groups and the higher rates of complications and mortality.Reference Smith, Jr, Clark, Cooper, Daniels, Kumanyika, Ofili, Quinones, Sanchez, Saunders and Tiukinhoy79
Obesity and cancer
More than 60% of cancers occur over the age of 65.84 In the last decade, findings in cancer epidemiology have highlighted the importance of the relationship between obesity and cancer.Reference Renehan and McTiernan85 Increased body mass and adiposity have been established as risk factors for the development of cancers that affect a large portion of the older adult population, such as colon cancer, breast cancer and prostate cancer.Reference Renehan and McTiernan85 Three hormonal systems have been proposed as causal pathways: insulin and insulin-like growth factor axis, sex steroids and adipokines.Reference Renehan and McTiernan85, Reference Renehan, Roberts and Dive86 These hormonal systems are altered in obesity; however, their role in the development of cancer is probably different for each cancer site. Additionally, the link between obesity and cancer seems to be different for men and women.Reference Renehan and McTiernan85–Reference Kelly, Yang, Chen, Reynolds and He87
To date there have been no clinical trials exploring the effect of losing weight, or even maintaining weight, on cancer incidence.Reference Renehan and McTiernan85, Reference Renehan, Roberts and Dive86 However, there is evidence from observational studies that weight maintenance and controlled weight loss may decrease the risk of developing some types of cancers.Reference Frezza, Wachtel and Chiriva-Internati88, 89 Despite the limited information, it has been shown that obesity increases the risk of delayed cancer diagnosis, complications during cancer treatment and poor outcomes after treatment.Reference Renehan, Soerjomataram and Leitzmann90, Reference Roberts, Dive and Renehan91
Obesity and arthritis
A common limitation when addressing arthritis in older adults is the lack of differentiation between the types of arthritis described. The most common types of arthritis affecting older adults are osteoarthritis, rheumatoid arthritis and gout. The pathophysiology, treatment and course of each type of arthritis are very different. However, the negative effect of arthritis on older adults is mostly due to its effect on overall physical and mental health and disability, rather than a direct increase in mortality risk.Reference Reynolds and McIlvane92
The relationship between obesity and arthritis has not been completely explained. Despite the differences in the most common types of arthritis in older adults, both obesity and arthritis are pro-inflammatory conditions that increase the concentration of cytokines and adipokines as previously reported.Reference Gomez, Lago, Gomez-Reino, Dieguez and Gualillo93 Additionally, arthritis impairs physical activity, necessary for weight loss and a cornerstone for self-management of arthritis because it diminishes pain and improves physical function.Reference Reynolds and McIlvane92, Reference Stavropoulos-Kalinoglou, Metsios, Koutedakis and Kitas94 Both increased levels of inflammatory markers and decreased physical activity in relation to obesity impede adequate management of arthritis and increase the long-term effects of the disease.Reference Toivanen, Heliovaara, Impivaara, Arokoski, Knekt, Lauren and Kröger95 In addition, obesity accelerates the deterioration of joint function in older adults with arthritis and negatively affects some outcomes from surgical interventions.Reference Reynolds and McIlvane92, Reference Toivanen, Heliovaara, Impivaara, Arokoski, Knekt, Lauren and Kröger95
Obesity and some geriatric syndromes
Obesity has been linked to some geriatric syndromes. The pro-inflammatory state caused by obesity has been linked to age-related muscle loss or sarcopenia.Reference Zamboni, Mazzali, Zoico, Harris, Meigs, Di Francesco, Fantin, Bissoli and Bosello4, Reference Zoico, Di Francesco, Guralnik, Mazzali, Bortolani, Guariento, Sergi, Bosello and Zamboni50 Sarcopenia has been shown to increase disability and overall mortality and may explain some of the complications reported in obese older adults.Reference Zamboni, Mazzali, Zoico, Harris, Meigs, Di Francesco, Fantin, Bissoli and Bosello4 Sarcopenia and obesity are independent conditions with separate pathophysiological pathways. However, older adults with co-morbid sarcopenia and obesity have become the centre of several studies. Co-occurrence of sarcopenia and obesity places older adults in a unique state of disease that increases the risk of adverse events and requires special interventions.Reference Zamboni, Mazzali, Zoico, Harris, Meigs, Di Francesco, Fantin, Bissoli and Bosello4, Reference Zoico, Di Francesco, Guralnik, Mazzali, Bortolani, Guariento, Sergi, Bosello and Zamboni50, Reference Rolland, Lauwers-Cances, Cristini, Abellan Van, Janssen, Morley and Vellas52, Reference Woo, Leung and Kwok54 Additionally, the pro-inflammatory state has also been related to vascular dysfunction in the brain that increases the production of beta-amyloid, a key component of senile plaques that accumulate in the brain in Alzheimer's disease.Reference Craft96–Reference Xu, Atti, Gatz, Pedersen, Johansson and Fratiglioni98
In summary, the pro-inflammatory state caused by obesity, in addition to the limitations in physical function, are common links to the added burden of disease when obesity is present concomitantly with many chronic conditions in older adults. Additionally, obesity is a marker of poor outcomes for most interventions for chronic conditions and interferes with management of most chronic diseases in older adults.
Conclusion
Obesity among older adults has increased noticeably in the last two decades in all continents. However, large variations between countries, race/ethnic groups and genders are observed. Obesity is related to increased risk of disability among older adult populations regardless of the measures used. Obesity affects functional status and mobility. Inflammation caused by obesity is linked to the added burden of disease when obesity is present concomitantly with many chronic conditions in older adults. Additionally, it is a marker of poor outcomes for most interventions for chronic conditions and interferes with management of most chronic diseases in older adults.
Policy makers and healthcare providers need to keep obesity-related health outcomes in mind and design obesity prevention and management programmes that can improve functional status in older adults and protect them from becoming disabled with resultant poor quality of life.
Conflicts of interest
The authors have nothing to disclose.
Acknowledgements
This study was supported by grants R03-AG029959, R01-AG017638 and R01-AG010939 from the National Institute on Aging, USA. Dr Al Snih is supported by a research career development award (K12HD052023: Building Interdisciplinary Research Careers in Women's Health Program–BIRCWH) from the Eunice Kennedy Shriver National Institute of Child Health & Human Development; the National Institute of Allergy and Infectious Diseases; and the Office of the Director, National Institutes of Health.
