12th December 2021, Dr Chee L Khoo
We touched on the subject of osteosarcopenia on a number of occasions over the years. These are people who have weak bones and have lost muscles. These are often older patients that have become weak for various reasons. Aging reduces the quality and strength of bones and muscles and increases body fat, which lead to the simultaneous occurrence of sarcopenia, osteopenia, and adiposity. You will not be surprised that there is an association between this triad and metabolic syndrome.
In Australia, a boy born in 2017–2019 can expect to live to the age of 80.9 years and a girl would be expected to live to 85.0 years compared to 51.1 and 54.8 years, respectively, in 1891–1900 (1). We ranked between 6-8th in world rankings for life expectancy. Great but what is the quality of life like? According to 2016 World Health Organization research, Australia’s healthy life expectancy – years of “full health” without disease or injury is 73 years which is about 10 years which means the last 7-10 years of life is lived with some form of disability. Generally, this 10-year gap is caused by diseases and loss of physical function that hinder independent living [2]. Therefore, it is especially important that adults nearing middle age take steps to prevent diseases and loss of physical function.
In your older patients, fat infiltrate into bone and muscles leading to osteopenia and sarcopenia. This not only leads to loss of physical function with decline in endurance, increasing weakness, fractures and loss of independent living but also metabolic and endocrine disturbances. Hence, the term osteo-sarcopenic adiposity (OSA), combining the occurrence of osteopenia, sarcopenia and adiposity.
A recent study in Taiwan explored the relationship between the prevalence of metabolic syndrome and OSA in the middle-aged and elderly populations (2). Taiwan has similar average life expectancy (81 years) and average healthy life expectancy (71 years). This cross-sectional study used data from a sample of individuals whose information was included in the Eonway Health Management Center database, which was collected in 2016–2018. The data was obtained from physical examinations and questionnaire responses. The study subjects were all Taiwanese and above 50 years of age from urban areas. They had undergone a self-financed health check-up and had completed fitness exam questionnaire items.
Subjects were divided into 4 groups according to the severity of the OSA:
- OSA 0 controls – no osteosarcopenic adiposity
- OSA 1 – those with either adiposity, sarcopenia, or osteoporosis
- OSA 2 – those with any two of adiposity, sarcopenia or osteoporosis and
- OSA 3 – those with all three conditions i.e., adiposity, sarcopenia, and osteoporosis
Metabolic syndrome was present if the subjects satisfied 3 of the 5 criteria:
- Waist circumference ≧90cm in males or ≧80cm in females
- Systolic BP ≧130 mmHg and/or diastolic BP ≧85 mmHg or taking antihypertensive agents
- Fasting blood glucose ≧5.5 mmol/L or taking anti-diabetic agents
- Fasting triglycerides≧1.7 mmol/L or taking hypolipidemic agents
- HDL < 1 mmol/L in males or < 1.3 mmol/L in females
Osteopenia was defined as T-score < -1.0. Adiposity was defined when body fat percentage was >25%.
Results
There were 1733 respondents. 58% were males with an average age of 58.55 years. 93.1% were living with family, 57.3% were working full time, and 41.1% walked or participated in moderate intensity exercise. Most of the respondents did not have hypertension (74.3%), hyperlipidaemia (83.7%), diabetes (88.4%), or cardiovascular diseases (95.4%). Finally, 77.5% respondents did not have metabolic syndrome.
Metabolic syndrome was found to be a significant factor among the four OSA groups after adjusting for other variables. This positive relationship between metabolic syndrome and OSA is in line with previous studies indicating that metabolic syndrome contributed not only to OSA but also to osteoporosis, sarcopenia, and adiposity [3-5].
In particular, for a subject who has metabolic syndrome, the odds ratio of having OSA 1, OSA 2 and OSA 3 is 1.4 X, 2.5X and 2.6X respectively. Expectedly, the older the subject was, the higher the risk of developing OSA. Compared to respondents who reported moderate intensity exercises, subjects who reported either walking/strolling and subjects who reported no exercises were 1.5X and 1.6X higher risk of developing OSA respectively.
Subjects who worked part-time or had retired had a lower likelihood of having OSA compared with those who worked full time. This finding is not consistent with those other studies indicating that retired people experience diminishing muscle strength [6]. Perhaps, those working full time have less time to exercise or are in the lower social economic ladder and are in poorer health generally.
As family physicians, we need to be pro-active in preventing muscle and bone loss and fat gain in patients during their later years. “Regular exercise” recommendations not only include regular aerobic exercises like walking, light jogging or swimming but must include weight bearing and balance exercises.
“We don’t get old and weak” but rather, “we get old when we become weak”.
References:
- https://www.aihw.gov.au/reports/life-expectancy-death/deaths-in-australia/contents/life-expectancy. Accessed 11th December 2021
- Su YH, Chang YM, Kung CY, Sung CK, Foo WS, Wu MH, Chiou SJ. A study of correlations between metabolic syndrome factors and osteosarcopenic adiposity. BMC Endocr Disord. 2021 Oct 29;21(1):216. doi: 10.1186/s12902-021-00880-w
- Wani K, Yakout SM, Ansari MGA, Sabico S, Hussain SD, Alokail MS, et al. Metabolic syndrome in Arab adults with low bone mineral density. Nutrients. 2019;11(6):1405. https://doi.org/10.3390/nu11061405.
- 21. Park S-J, Ryu SY, Park J, Choi SW. Association of Sarcopenia with metabolic syndrome in Korean population using 2009–2010 Korea National Health and nutrition examination survey. Metab Syndr Relat Disord. 2019;17(10): 494–9. https://doi.org/10.1089/met.2019.0059.
- 22. Dominguez LJ, Barbagallo M. The biology of the metabolic syndrome and aging. Curr Opin Clin Nutri Metab Care. 2016;19(1):5–11. https://doi.org/10.1097/MCO.0000000000000243
- Bertoni M, Maggi S, Weber G. Work, retirement, and muscle strength loss in old age. Health Econ. 2018;27(1):115–28. https://doi.org/10.1002/hec.3517.