Sari Stenholm

The effect of obesity combined with low muscle strength on decline in mobility in older persons: results from the InCHIANTI Study

Objective:Both obesity and muscle impairment are increasingly prevalent among older persons and negatively affect health and physical functioning. However, the combined effect of coexisting obesity and muscle impairment on physical function decline has been little studied. We examined whether obese persons with low muscle strength experience significantly greater declines in walking speed and mobility than persons with only obesity or low muscle strength.Design:Community-dwelling adults aged ⩾65 years (n=930) living in the Chianti geographic area (Tuscany, Italy) were followed for 6 years in the population-based InCHIANTI study.Measurements:On the basis of baseline measurements (1998–2000), obesity was defined as body mass index (BMI) ⩾30u2009kg/m2 and low muscle strength as lowest sex-specific tertile of knee extensor strength. Walking speed and self-reported mobility disability (ability to walk 400u2009m or climb one flight of stairs) were assessed at baseline and at 3- and 6-year follow-up.Results:At baseline, obese persons with low muscle strength had significantly lower walking speed compared with all other groups (P⩽0.05). In longitudinal analyses, obese participants with low muscle strength had steeper decline in walking speed and high risk of developing new mobility disability over the 6-year follow-up compared with those without obesity or low muscle strength. After the age of 80, the differences between groups were substantially attenuated. The differences seen in walking speed across combination of low muscle strength and obesity groups were partly explained by 6-year changes in muscle strength, BMI and waist circumference.Conclusions:Obesity combined with low muscle strength increases the risk of decline in walking speed and developing mobility disability, especially among persons <80 years old.

Body fat distribution and inflammation among obese older adults with and without metabolic syndrome.

The protective mechanisms by which some obese individuals escape the detrimental metabolic consequences of obesity are not understood. This study examined differences in body fat distribution and adipocytokines in obese older persons with and without metabolic syndrome. Additionally, we examined whether adipocytokines mediate the association between body fat distribution and metabolic syndrome. Data were from 729 obese men and women (BMI ≥30 kg/m2), aged 70–79 participating in the Health, Aging and Body Composition (Health ABC) study. Thirty‐one percent of these obese men and women did not have metabolic syndrome. Obese persons with metabolic syndrome had significantly more abdominal visceral fat (men: P = 0.04; women: P < 0.01) and less thigh subcutaneous fat (men: P = 0.09; women: P < 0.01) than those without metabolic syndrome. Additionally, those with metabolic syndrome had significantly higher levels of interleukin‐6 (IL‐6), tumor necrosis factor‐α (TNF‐α), and plasminogen activator inhibitor‐1 (PAI‐1) than individuals without metabolic syndrome. Per standard deviation higher in visceral fat, the likelihood of metabolic syndrome significantly increased in women (odds ratio (OR): 2.16, 95% confidence interval (CI): 1.59–2.94). In contrast, the likelihood of metabolic syndrome decreased in both men (OR: 0.56, 95% CI: 0.39–0.80) and women (OR: 0.49, 95% CI: 0.34–0.69) with each standard deviation higher in thigh subcutaneous fat. These associations were partly mediated by adipocytokines; the association between thigh subcutaneous fat and metabolic syndrome was no longer significant in men. In summary, metabolically healthy obese older persons had a more favorable fat distribution, characterized by lower visceral fat and greater thigh subcutaneous fat and a more favorable inflammatory profile compared to their metabolically unhealthy obese counterparts.

Does the Amount of Fat Mass Predict Age-Related Loss of Lean Mass, Muscle Strength, and Muscle Quality in Older Adults?

BACKGROUNDnAn excessive amount of adipose tissue may contribute to sarcopenia and may be one mechanism underlying accelerated loss of muscle mass and strength with aging. We therefore examined the association of baseline total body fat with changes in leg lean mass, muscle strength, and muscle quality over 7 years of follow-up and whether this link was explained by adipocytokines and insulin resistance.nnnMETHODSnData were from 2,307 men and women, aged 70-79 years, participating in the Health, Aging, and Body Composition study. Total fat mass was acquired from dual energy X-ray absorptiometry. Leg lean mass was assessed by dual energy X-ray absorptiometry in Years 1, 2, 3, 4, 5, 6, and 8. Knee extension strength was measured by isokinetic dynamometer in Years 1, 2, 4, 6, and 8. Muscle quality was calculated as muscle strength divided by leg lean mass.nnnRESULTSnEvery SD greater fat mass was related to 1.3 kg more leg lean mass at baseline in men and 1.5 kg in women (p < .01). Greater fat mass was also associated with a greater decline in leg lean mass in both men and women (0.02 kg/year, p < .01), which was not explained by higher levels of adipocytokines and insulin resistance. Larger fat mass was related to significantly greater muscle strength but significantly lower muscle quality at baseline (p < .01). No significant differences in decline of muscle strength and quality were found.nnnCONCLUSIONSnHigh fatness was associated with lower muscle quality, and it predicts accelerated loss of lean mass. Prevention of greater fatness in old age may decrease the loss of lean mass and maintain muscle quality and thereby reducing disability and mobility impairments.

Hand-Grip Strength Cut Points to Screen Older Persons at Risk for Mobility Limitation

OBJECTIVES: To determine optimal hand‐grip strength cut points for likelihood of mobility limitation in older people and to study whether these cut points differ according to body mass index (BMI).

Sleep-related factors and mobility in older men and women.

BACKGROUNDnTo examine the association between sleep-related factors and measured and self-reported mobility in a representative sample of older adults.nnnMETHODSnThis study included 2,825 men and women aged 55 years and older participating in a cross-sectional representative population-based Health 2000 Survey in Finland. Sleep duration, insomnia-related symptoms, and fatigue were inquired. Maximal walking speed was measured, and mobility limitation was defined as self-reported difficulties in walking 500 m or stair climbing.nnnRESULTSnInsomnia-related symptoms and fatigue were prevalent among persons aged 65 years and older in particular. After adjusting for lifestyle factors and diseases, longer sleep (>/=9 hours) was associated with a decreased walking speed in women aged 65 or more years (p = .04) and shorter sleep (</=6 hours) with a higher odds for mobility limitation in women aged 65 or more years (odds ratio [OR] = 1.68, 95% confidence interval [CI] = 1.02-2.75) and in men aged 55-64 years (OR = 3.62, 95% CI = 1.40-9.37) compared with those having a mid-range sleep duration. Sleeping disorders or insomnia was independently associated with both decreased walking speed and mobility limitation in men aged 55 or more years but only with mobility limitation in women aged 65 or more years. Of the sleep-related daytime consequences, weakness or tiredness was associated with a decreased walking speed and a higher odds for mobility limitation both in men and in women aged 55 or more years.nnnCONCLUSIONSnSeveral sleep-related factors, such as sleep duration, insomnia-related symptoms, and fatigue, are associated with measured and self-reported mobility outcomes.

Joint Association of Obesity and Metabolic Syndrome With Incident Mobility Limitation in Older Men and Women—Results From the Health, Aging, and Body Composition Study

BACKGROUNDnAlthough both obesity and the metabolic syndrome (MetS) are known risk factors for decline in physical function, the joint association of obesity and metabolic alterations with risk of incident mobility limitation is unknown.nnnMETHODSnData are from 2,984 women and men aged 70-79 years participating in the Health, Aging, and Body Composition Study without mobility limitation at baseline. Obesity was defined as body mass index greater than or equal to 30 kg/m(2) and the MetS as meeting greater than or equal to 3 of the ATP III criteria. Mobility limitation was defined as any difficulty walking one-quarter mile or climbing 10 steps during two consecutive semiannual assessments for more than 6.5 years.nnnRESULTSnIncidence of mobility limitation was 55% in women and 44% in men. In women, adjusted risk of developing mobility limitation was progressively greater in nonobese participants with the MetS (hazard ratio [HR] = 1.49, 95% confidence interval [CI] = 1.24-1.80), obese participants without the MetS (HR = 1.95, 95% CI = 1.51-2.53), and obese participants with the MetS (HR = 2.16, 95% CI = 1.78-2.63) relative to the nonobese without the MetS. In men, the corresponding adjusted HRs (95% CI) were 1.07 (0.87-1.32), 1.64 (1.19-2.25), and 1.41 (1.12-1.78). Elevated inflammatory markers partly explained the association between obesity, the MetS, and mobility limitation, particularly in nonobese and obese participants with the MetS.nnnCONCLUSIONSnObesity itself, independent of its metabolic consequences, is a risk factor for mobility limitation among obese older adults. In addition, having the MetS increases the risk of functional decline in older nonobese women but not in men.

Adipocytokines and the metabolic syndrome among older persons with and without obesity – the InChianti Study.

Objectivesu2002 Adipose tissue‐derived inflammation may contribute to metabolic alterations and eventually to the metabolic syndrome (MetS). The purpose of this study was to: (1) examine the role of adipocytokines in the association between obesity and the MetS and (2) to determine whether the association is different in obese and non‐obese persons.

Secular trends in body weight in older men born between 1877 and 1941: the Baltimore Longitudinal Study of Aging.

BACKGROUNDnThe prevalence of overweight and obesity has increased in all age groups, including older adults. However, it is not known whether higher body weight is maintained in the very old and in the years prior to death. The present study examines whether there are secular trends in body weight in old age among three birth cohorts.nnnMETHODSnThe study population includes 1,364 Caucasian men born between 1877 and 1941 from the Baltimore Longitudinal Study of Aging who were followed until death. Four hundred and seventy-seven men had body weight measured during the last 5 years prior to death. Body weight was measured biannually with the last visit occurring between 1959 and 2008. Differences in body weight at the last visit and body weight trajectories across birth cohorts were examined with linear regression and linear mixed-effect regression models.nnnRESULTSnMen born between 1920 and 1941 had significantly higher body weight over the entire follow-up time compared with men born between 1900 and 1919 (p < .001) and 1877 and 1899 (p = .001), and the difference was also significant between the two earlier birth cohorts (p < .001). A significant increasing trend in body weight across birth cohorts was also observed in the few years prior to death.nnnCONCLUSIONSnIn generally healthy men, there is a significant secular increase in body weight over the adult life span and in the few years prior to death. This study confirms that the obesity epidemic also extends into late life in the current elderly population.