Lance E. Davidson

Age-related changes in total and regional fat distribution.

Aging is associated with progressive changes in total and regional fat distribution that have negative health consequences. Indeed, a preferential increase in abdominal fat, in particular visceral fat, combined with a decrease in lower body subcutaneous fat are commonly cited in the literature. These age-related changes in body composition can occur independent of changes in total adiposity, body weight or waist circumference, and represent a phenotype closely associated with increased morbidity and mortality risk. Tissues such as the heart, liver and skeletal muscle in the elderly have increased fat deposition, which increases risk for insulin resistance and cardiovascular disease. Furthermore, aging is associated with increased fat content within bone marrow, which exposes the elderly to fracture risk beyond that associated with low bone mineral density alone. Many of the age-associated body compositional changes cannot be detected by simple anthropometric measures alone, and the influence of gender, race or ethnicity, and physical activity patterns on these changes is unclear. This review will explore some of these age-related changes in total and regional fat distribution. Consideration will also be given to the strengths and limitations associated with some of the anthropometric methodologies employed for assessing these changes.

Effects of Exercise Modality on Insulin Resistance and Functional Limitation in Older Adults: A Randomized Controlled Trial

BACKGROUND Authorities advocate that resistance and aerobic exercise are essential for reducing risk factors for chronic disease and disability in older adults. However, the incremental effects of combined resistance and aerobic exercise compared with either modality alone on risk factors for disease and disability is generally unknown. METHODS Participants were 136 sedentary, abdominally obese older men and women recruited from September 30, 2002, through November 15, 2006, at Queens University. Participants were randomized to 1 of the following 4 groups for 6 months: resistance exercise, aerobic exercise, resistance and aerobic exercise (combined exercise), or nonexercise control. Primary outcomes were analyzed by an intent-to-treat model and included changes in insulin resistance by hyperinsulinemic-euglycemic clamp and functional limitation using the average change in 4 tests combined (average z score). RESULTS After controlling for age, sex, and baseline value, insulin resistance improved compared with controls in the aerobic exercise and the combined exercise groups but not in the resistance exercise group. Improvement (mean [SE]) in the combined exercise group was greater than in the resistance exercise group (9.2 [1.3] vs 1.8 [1.3] mg/mL/microIU per kilogram of skeletal muscle per minute x100 [P < .001]) but not in the aerobic exercise group (9.2 [1.3] vs 6.5 [1.3] mg/mL/microIU per kilogram of skeletal muscle per minute x100 [P = .46]). Functional limitation improved significantly in all groups compared with the control group. Improvement in the combined exercise group was greater than in the aerobic exercise group (0.5 [0.1] vs -0.0 [0.1]; standard units, z score [P = .003]) but not in the resistance exercise group. Improvement in the resistance exercise group was not different from the aerobic exercise group. CONCLUSION The combination of resistance and aerobic exercise was the optimal exercise strategy for simultaneous reduction in insulin resistance and functional limitation in previously sedentary, abdominally obese older adults. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00520858.

Six-year changes in health-related quality of life in gastric bypass patients versus obese comparison groups

BACKGROUND Few studies have evaluated the long-term outcomes of bariatric surgery patients in relation to obese individuals not participating in weight loss interventions. Our objective was to evaluate the 6-year changes in health-related quality of life (HRQOL) in gastric bypass (GB) patients versus 2 obese groups not undergoing surgical weight loss. The study setting was a bariatric surgery practice. METHODS A total of 323 GB patients were compared with 257 individuals who sought but did not undergo gastric bypass and 272 population-based obese individuals using weight-specific (impact of weight on quality of life-lite) and general (medical outcomes study short-form 36 health survey) HRQOL questionnaires at baseline and 2 and 6 years later. RESULTS At 6 years, compared with the controls, the GB group exhibited significant improvements in all domains of weight-specific and most domains of general HRQOL (i.e., all physical and some mental/psychosocial). The 6-year percentage of excess weight loss correlated significantly with improvements in both weight-specific and physical HRQOL. The HRQOL scores were fairly stable from 2 to 6 years for the GB group, with small decreases in HRQOL corresponding to some weight regain. CONCLUSIONS GB patients demonstrated significant improvements in most aspects of HRQOL at 6 years compared with 2 nonsurgical obese groups. Despite some weight regain and small decreases in HRQOL from 2 to 6 years postoperatively, the HRQOL was relatively stable. These results support the effectiveness of weight loss achieved with gastric bypass surgery for improving and maintaining long-term HRQOL.

Weight and Metabolic Outcomes 12 Years after Gastric Bypass

BACKGROUND Few long‐term or controlled studies of bariatric surgery have been conducted to date. We report the 12‐year follow‐up results of an observational, prospective study of Roux‐en‐Y gastric bypass that was conducted in the United States. METHODS A total of 1156 patients with severe obesity comprised three groups: 418 patients who sought and underwent Roux‐en‐Y gastric bypass (surgery group), 417 patients who sought but did not undergo surgery (primarily for insurance reasons) (nonsurgery group 1), and 321 patients who did not seek surgery (nonsurgery group 2). We performed clinical examinations at baseline and at 2 years, 6 years, and 12 years to ascertain the presence of type 2 diabetes, hypertension, and dyslipidemia. RESULTS The follow‐up rate exceeded 90% at 12 years. The adjusted mean change from baseline in body weight in the surgery group was ‐45.0 kg (95% confidence interval [CI], ‐47.2 to ‐42.9; mean percent change, ‐35.0) at 2 years, ‐36.3 kg (95% CI, ‐39.0 to ‐33.5; mean percent change, ‐28.0) at 6 years, and ‐35.0 kg (95% CI, ‐38.4 to ‐31.7; mean percent change, ‐26.9) at 12 years; the mean change at 12 years in nonsurgery group 1 was ‐2.9 kg (95% CI, ‐6.9 to 1.0; mean percent change, ‐2.0), and the mean change at 12 years in nonsurgery group 2 was 0 kg (95% CI, ‐3.5 to 3.5; mean percent change, ‐0.9). Among the patients in the surgery group who had type 2 diabetes at baseline, type 2 diabetes remitted in 66 of 88 patients (75%) at 2 years, in 54 of 87 patients (62%) at 6 years, and in 43 of 84 patients (51%) at 12 years. The odds ratio for the incidence of type 2 diabetes at 12 years was 0.08 (95% CI, 0.03 to 0.24) for the surgery group versus nonsurgery group 1 and 0.09 (95% CI, 0.03 to 0.29) for the surgery group versus nonsurgery group 2 (P<0.001 for both comparisons). The surgery group had higher remission rates and lower incidence rates of hypertension and dyslipidemia than did nonsurgery group 1 (P<0.05 for all comparisons). CONCLUSIONS This study showed long‐term durability of weight loss and effective remission and prevention of type 2 diabetes, hypertension, and dyslipidemia after Roux‐en‐Y gastric bypass. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.)

Brain and high metabolic rate organ mass: contributions to resting energy expenditure beyond fat-free mass

BACKGROUND The degree to which interindividual variation in the mass of select high metabolic rate organs (HMROs) mediates variability in resting energy expenditure (REE) is unknown. OBJECTIVE The objective was to investigate how much REE variability is explained by differences in HMRO mass in adults and whether age, sex, and race independently predict REE after adjustment for HMRO. DESIGN A cross-sectional evaluation of 55 women [30 African Americans aged 48.7 +/- 22.2 y (mean +/- SD) and 25 whites aged 46.4 +/- 17.7 y] and 32 men (8 African Americans aged 34.3 +/- 18.2 y and 24 whites aged 51.3 +/- 20.6 y) was conducted. Liver, kidney, spleen, heart, and brain masses were measured by magnetic resonance imaging, and fat and fat-free mass (FFM) were measured by dual-energy X-ray absorptiometry. REE was measured by indirect calorimetry. RESULTS REE estimated from age (P = 0.001), race (P = 0.006), sex (P = 0.31), fat (P = 0.001), and FFM (P < 0.001) accounted for 70% (adjusted (2)) of the variability in REE. The addition of trunk HMRO (P = 0.001) and brain (P = 0.006) to the model increased the explained variance to 75% and rendered the contributions of age, sex, and race statistically nonsignificant, whereas fat and FFM continued to make significant contributions (both P < 0.05). The addition of brain to the model rendered the intercept (69 kcal . kg(-1) . d(-1)) consistent with zero, which indicated zero REE for zero body mass. CONCLUSIONS Relatively small interindividual variation in HMRO mass significantly affects REE and reduces the role of age, race, and sex in explaining REE. Decreases in REE with increasing age may be partly related to age-associated changes in the relative size of FFM components.

Whole-body skeletal muscle mass is not related to glucose tolerance or insulin sensitivity in overweight and obese men and women

The relationship between skeletal muscle mass, visceral adipose tissue, insulin sensitivity, and glucose tolerance was examined in 214 overweight or obese, but otherwise healthy, men (n = 98) and women (n = 116) who participated in various exercise and (or) weight-loss intervention studies. Subjects had a 75 g oral glucose tolerance test and (or) insulin sensitivity measures by a 3 h hyperinsulinemic-euglycemic clamp technique. Whole-body skeletal muscle mass and visceral adipose tissue were measured using a multi-slice magnetic resonance imaging protocol. Total body skeletal muscle mass was not associated with any measure of glucose metabolism in men or women (p > 0.10). These observations remained independent of age and total adiposity. Conversely, visceral adipose tissue was a significant predictor of various measures of glucose metabolism in both men and women with or without control for age and (or) total body fat (p < 0.05). Although skeletal muscle is a primary site for glucose uptake and deposition, these findings suggest that unlike visceral adipose tissue, whole-body skeletal muscle mass per se is not associated with either glucose tolerance or insulin sensitivity in overweight and obese men and women.

Albuminuria is strongly associated with arterial stiffness, especially in diabetic or hypertensive subjects—A population-based study (Taichung Community Health Study, TCHS)

OBJECTIVE Albuminuria is recognized as a marker of vascular dysfunction. Brachial-ankle pulse wave velocity (baPWV) reflects the stiffness of central and peripheral muscular arteries. Limited information is available for the association between albuminuria and arterial stiffness in Chinese. We aimed to assess the association between albuminuria and arterial stiffness in a middle-aged population-based study. METHODS A total of 2180 subjects aged 40 years and over were recruited in 2004 in Taiwan. Albuminuria was defined as urinary albumin-to-creatinine ratio (ACR)>or=30 mg/g creatinine. BaPWV was divided by quartile. Multiple logistic and linear regression analyses were used to evaluate the relationship between baPWV and albuminuria. RESULTS After adjusting for age, body mass index, mean arterial pressure, fasting glucose, triglycerides, total cholesterol, chronic kidney disease, smoking, alcohol drinking, and physical activity status, multiple logistic regression analyses revealed baPWV groups were significantly associated with albuminuria. Compared to the lowest baPWV quartile, the adjusted odds ratio of having albuminuria for baPWV quartile II, III, and IV were 1.12(0.63-2.02), 2.04(1.15-3.60), and 2.45(1.29-4.65). The significant increase in odds ratios for albuminuria in progressive baPWV quartiles reveals a dose-response effect (p<0.001). Among diabetic, hypertensive, and macroalbuminuria subjects, these relationships were stronger than in subjects without diabetes, hypertension, and microalbuminuria. Moreover, multiple linear regression analyses showed that baPWV was significantly associated with urinary ACR after adjusting for potential confounders. CONCLUSION Albuminuria was strongly related to arterial stiffness among Chinese middle-aged adults. These relationships were enhanced in subjects with hypertension, diabetes, or macroalbuminuria.

Predicting Fat Percent by Skinfolds in Racial Groups: Durnin and Womersley Revisited

PURPOSE Despite their widespread use in research and fitness settings, Durnin and Womersleys (DW) 1974 prediction equations using skinfold thickness to estimate body fat percent by hydrodensitometry have not been systematically evaluated in racial or ethnic groups using body fat percent measured by dual-energy x-ray absorptiometry (%BF(DXA)) as the standard. METHODS This cross-sectional, population-based study examined whether the DW skinfold equations predict %BF(DXA) in a large, multiracial sample. Four skinfold measures (biceps, triceps, subscapular, and suprailiac), other clinical anthropometrics, and %BF(DXA) were obtained from 1675 healthy adults, age 18-110 yr, who were classified into four racial or ethnic categories: Caucasian, African American, Hispanic, or Asian. Predicted body fat percent using DW equations was compared with %BF(DXA) and evaluated within race/ethnicity- and sex-specific groups. RESULTS Mean body fat percent predicted by DW equations was significantly different from %BF(DXA) in four of eight race/ethnicity- and sex-specific groups, particularly in Asian women and African American men (3.3 and 2.4 percentage point overestimates, respectively, P < 0.0001). New linear regression equations were developed estimating %BF(DXA) specific to each race/ethnicity and sex group, using the original DW skinfold sites. Body weight, height, and waist circumference independently predicted fat percent and were also included in the new equations. CONCLUSIONS The 1974 DW equations did not predict %BF(DXA) uniformly in all races or ethnicities. Using %BF(DXA) as the criterion measure, the original DW skinfold equations have been updated specific to sex and race/ethnicity while maintaining the DW options for a minimalistic model using fewer predictors.

Coffee consumption is inversely associated with type 2 diabetes in Chinese

Eur J Clin Invest 2011; 41 (6): 659–666

Medical expenditure and family satisfaction between hospice and general care in terminal cancer patients in Taiwan

BACKGROUND/PURPOSE As the number of terminal cancer patients increases, several care models have been adopted to provide better care quality and reduce medical expenditure. This study compared inpatient medical expenditure and family satisfaction in a hospice ward (HW) and general ward (GW) for terminal cancer patients in Taiwan. METHODS We enrolled terminal cancer patients who were admitted and died during the same admission period in a tertiary care hospital in Taiwan from January 2003 to December 2005. These patients were allocated into three groups: inpatient care in HW alone; inpatient care in GW alone; and inpatient care in mixed group (initially in GW, then transferred to HW). Inpatient medical expenditure and family satisfaction were compared between the three groups. RESULTS A total of 1942 patients were recruited and allocated into HW (n = 292), GW (n = 1511) and mixed (n = 139) groups. The average medical expenditure per person or per inpatient day was lower in the HW than the GW or mixed group. Subjects who had ever been admitted to the intensive care unit or received cardiopulmonary resuscitation in the GW or mixed groups required more expenditure on medical care than that in the HW group. Daily medical expenditure in the HW group also was much lower than that in the GW and mixed groups, based on length of stay and cancer type. The family satisfaction score was significantly higher in the mixed and/or HW group than the GW group. CONCLUSION For terminal cancer patients, hospice care can improve family satisfaction while reducing medical expenditure in Taiwan.