Association of thyroid function with insulin resistance: data from two population-based studies.

OBJECTIVE: Thyroid dysfunction is associated with relevant disturbances in glucose metabolism. Moreover, thyroid function undergoes important changes with ageing. The objective of this study was to investigate the association of thyroid function with insulin resistance with particular consideration of possible age-related effect modifications. DESIGN: A sample of 4193 participants from two independent epidemiological studies, the Study of Health in Pomerania-TREND-0 and the Berlin Aging Study II, was included in this cross-sectional analysis. METHODS: Insulin resistance was estimated by homeostasis model of insulin resistance (HOMA-IR) and the insulin sensitivity index (ISI). Associations of thyroid biomarkers (thyroid-stimulating hormone, free thyroxine, and free triiodothyronine (fT3)) with parameters of glucose metabolism were analysed by regression models adjusted for age, sex, smoking status, and study site. RESULTS: A higher fT3 was significantly associated with higher fasting glucose and higher fasting and 2-h postload insulin levels, a higher HOMA-IR, and lower ISI. A higher fT3 was also associated with a higher risk for impaired fasting glucose (RR 1.09, 95 CI 1.02; 1.18; P = 0.017). Many of these associations between thyroid markers and parameters of glucose metabolism were significant in young and middle-aged participants but not in older individuals. CONCLUSIONS: The main finding of this study was a consistent association of fT3 with almost all markers of insulin resistance. However, this effect seems to be wearing off in higher age highlighting a potential age-related modification of the interaction between thyroid function and glucose metabolism. Further studies are needed to clarify causal relationships.

Muscle Mass and Inflammation in Older Adults: Impact of the Metabolic Syndrome.

BACKGROUND: Inflammatory processes are a cause of accelerated loss of muscle mass. Metabolic syndrome (MetS) is a highly prevalent age-related condition, which may promote and be promoted by inflammation. However, whether inflammation in MetS (metaflammation) is associated with lower muscle mass is still unclear. METHODS: Complete cross-sectional data on body composition, MetS, and the inflammatory markers interleukin (IL)-1ß, IL-6, IL-10, tumor necrosis factor (TNF), and C-reactive protein (CRP) were available for 1,377 BASE-II participants (51.1% women; 68 ± 4 years old). Appendicular lean mass (ALM) was assessed by dual-energy X-ray absorptiometry. Low muscle mass (low ALM-to-BMI ratio [ALMBMI]) was defined according to the Foundation for the National Institutes of Health (FNIH) Sarcopenia Project. Regression models, adjusted for an increasing number of confounders (sex, age, physical activity, morbidities, diabetes mellitus type II, TSH, albumin, HbA1c, smoking habits, alcohol intake, education, and energy intake/day), were used to calculate the association between low ALMBMI and high inflammation (tertile 3) according to MetS. RESULTS: MetS was present in 36.2% of the study population, and 9% had low ALMBMI. In the whole study population, high CRP (odds ratio [OR]: 2.7 [95% CI: 1.6-4.7; p = 0.001]) and high IL-6 (OR: 2.1 [95% CI: 1.2-1.9; p = 0.005]) were associated with low ALMBMI. In contrast, no significant association was found between TNF, IL-10, or IL-1ß with low ALMBMI. When participants were stratified by MetS, results for IL-6 remained significant only in participants with MetS. CONCLUSIONS: Among BASE-II participants, low ALMBMI was associated with inflammation. Low-grade inflammation triggered by disease state, especially in the context of MetS, might favor loss of muscle mass, so a better control of MetS might help to prevent sarcopenia. Intervention studies to test whether strategies to prevent MetS might also prevent loss of muscle mass seem to be promising.

Lower muscular strength is associated with smaller left and right chambers and lower cardiac mass in the general population - The Sedentary's Heart.

BACKGROUND: The cardiac muscle has the ability to adapt to different loading conditions. We analyzed the associations of the age-related decreasing handgrip strength (HGS), a marker of muscular fitness, on cardiac structure and function in a community-based sample. METHODS: We performed cross-sectional analyses of 4646 subjects (2554 women; 55.0%) aged 20 to 93 years from two independent cohorts of the Study of Health in Pomerania (SHIP-2 and SHIP-TREND-0). We analyzed the associations of HGS with structural and functional left and right ventricular (LV and RV) and left atrial (LA) parameters as determined by echocardiography and magnetic resonance imaging (MRI) as well with log-transformed NT-proBNP values using multivariable-adjusted linear regression models. RESULTS: MRI data showed that a 1 kg lower HGS was associated with a 0.40 mL (95% confidence interval: 0.26 to 0.54; p < 0.001) lower LV end-diastolic volume, a 0.011 mm (0.005 to 0.018; p = 0.001) lower LV wall-thickness, a 0.59 g (0.43 to 0.75; p < 0.001) lower LV mass, a 0.58 mL/beat (0.43 to 0.74; p < 0.001) lower LV stroke volume, a 0.03 L/min (0.02 to 0.04; p < 0.001) lower LV cardiac output, a 0.48 mL (0.27 to 0.68; p < 0.001) lower LA end-diastolic volume, and a 1.02 mL (0.71 to 1.32) lower RV end-diastolic volume. Similar findings were observed for echocardiographic parameters. Moreover, lower HGS was associated with higher echocardiographic LV diastolic stiffness and NT-proBNP levels. CONCLUSIONS: In this large population-based sample, lower muscular fitness as assessed by HGS was associated with lower LV wall thickness and mass as well as with smaller chamber size, stroke volume and cardiac output of the LV, LA and RV. Moreover, HGS was inversely related to LV diastolic stiffness and NT-proBNP values. These outcomes might demonstrate the effects of an aging-related decrease in physical activity and lower muscular fitness on the heart - "the sedentary's heart".

Low muscle strength and increased arterial stiffness go hand in hand.

Low handgrip strength and increased arterial stiffness are both associated with poor health outcomes, but evidence on the relationship between handgrip strength and arterial stiffness is limited. In this cross-sectional analysis of combined baseline datasets from the LipidCardio and Berlin Aging Study II cohorts we aimed to examine whether handgrip strength (HGS) is associated with arterial stiffness. 1511 participants with a median age of 68.56 (IQR 63.13-73.08) years were included. Arterial stiffness was assessed by aortal pulse wave velocity (PWV) with the Mobil-O-Graph device. Handgrip strength was assessed with a handheld dynamometer.The mean HGS was 39.05 ± 9.07 kg in men and 26.20 ± 7.47 kg in women. According to multivariable linear regression analysis per 5 kg decrease in handgrip strength there was a mean increase in PWV of 0.08 m/s after adjustment for the confounders age, sex, coronary artery disease, systolic blood pressure, body mass index, cohort, and smoking. Thus, there was evidence that low handgrip strength and increased arterial stiffness go hand in hand. Arterial stiffness can possibly create the missing link between low handgrip strength and increased cardiovascular morbidity and mortality. Causality and direction of causality remain to be determined.

Problematic drinking in the old and its association with muscle mass and muscle function in type II diabetes.

Problematic drinking behavior is common in the old and negative consequences of hypoglycemic episodes in type 2 diabetes (T2D) as a result of alcohol consumption have been described previously. Although, associations between such hypoglycemic episodes with reduced muscle mass are discussed, it is uncertain if problematic drinking behavior drives decline of muscle mass and/or muscle function. In the current study, we analyzed data of the Berlin Aging Study II (BASE-II) to examine the association of problematic drinking behavior with muscle mass and grip strength in T2D. Cross-sectional data of 1451 old BASE-II participants (51.6% women; 60-84 years old) were analyzed. Problematic drinking behavior was assessed using the Alcohol Use Identification Test (AUDIT). Muscle mass was measured using dual energy X-ray absorptiometry (DXA), grip strength using a Smedley dynamometer. Adjusted regression models were calculated to assess the association of problematic drinking with muscle mass and grip strength. Problematic drinking was evident in 11.2% of BASE-II participants and in 12.5% of BASE-II participants diabetes was evident. In the fully adjusted model (adjusted for age, trunk fat mass, HbA1c, antidiabetic medication, TSH, CRP, testosterone, physical inactivity, depression (GDS-score), morbidities, smoking status and total energy intake/day, we found a statistically significant association between problematic drinking and muscle mass (ß-3.7, SE: 1.3, R2 0.481, partial eta square 0.166, observed power 0.816, p-value 0.005) and grip strength (ß-8.1, SE: 3.3, R2 0.222, partial eta square 0.134, observed power 0.670, p-value 0.018) in old diabetic men. These associations were not evident in women and subjects without T2D. Problematic drinking behavior was associated with lower muscle mass and grip strength in old men with diabetes. This topic should be addressed in these subjects as they could be at increased risk for early functional decline, sarcopenia or frailty.

Historical trends in modifiable indicators of cardiovascular health and self-rated health among older adults: Cohort differences over 20 years between the Berlin Aging Study (BASE) and the Berlin Aging Study II (BASE-II).

BACKGROUND: The last decades have seen great advances in the understanding, treatment, and prevention of cardiovascular disease (CVD). Although mortality rates due to CVD have declined significantly in the last decades, the burden of CVD is still high, particularly in older adults. This raises the question whether contemporary populations of older adults are experiencing better or worse objective as well as subjective health than earlier-born cohorts. The aim of this study was to examine differences in modifiable indicators of cardiovascular health (CVH), comparing data obtained 20 years apart in the Berlin Aging Study (BASE, 1990-93) and the Berlin Aging Study II (BASE-II, 2009-2014). METHODS: Serial cross-sectional analysis of 242 propensity-score-matched participants of BASE (born 1907-1922) and BASE-II (born 1925-1942). Body mass index (BMI), blood pressure, total cholesterol, glycated hemoglobin (HbA1c), diet, smoking and physical activity were operationalized according to the "Life's simple 7"(LS7) criteria of the American Heart Association. RESULTS: 121 matched pairs were identified based on age, sex, and education. In the later-born BASE-II sample, the mean LS7 score was significantly higher than in the earlier-born sample (7.8±1.8 vs. 6.4±2.1, p<0.001), indicating better CVH. In detail, diet, physical activity, smoking, cholesterol, and HbA1c were more favorable, whereas blood pressure was significantly higher in individuals from the later-born cohort. BMI did not differ significantly between the two matched samples. Notably, despite better CVH, later-born individuals (BASE-II) reported lower self-rated health, presumably because of higher health expectations. CONCLUSIONS: Overall, cardiovascular health was significantly better in the later-born cohort, but several notable exceptions exist.

Relative Leukocyte Telomere Length, Hematological Parameters and Anemia - Data from the Berlin Aging Study II (BASE-II).

BACKGROUND: The length of the chromosome ends, telomeres, is widely accepted as a biomarker of aging. However, the dynamic of the relationship between telomere length and hematopoietic parameters in the normal aging process, which is of particular interest with respect to age-related anemia, is not well understood. OBJECTIVE: We have analyzed the relationship between relative leukocyte telomere length (rLTL) and several hematological parameters in the older group of the Berlin Aging Study II (BASE-II) participants. This paper also compares rLTL between both BASE-II age groups (22-37 and 60-83 years). METHODS: Genomic DNA was extracted from peripheral blood leukocytes of BASE-II participants and used to determine rLTL by a quantitative PCR protocol. Standard methods were used to determine blood parameters, and the WHO criteria were used to identify anemic participants. RESULTS: Telomere length data were available for 444 younger participants (28.4 ± 3.1 years old; 52% women) and 1,460 older participants (68.2 ± 3.7 years old; 49.4% women). rLTL was significantly shorter in BASE-II participants of the older group (p = 3.7 × 10-12) and in women (p = 4.2 × 10-31). rLTL of older men exhibited a statistically significant, positive partial correlation with mean corpuscular hemoglobin (MCH; p = 0.012) and MCH concentration (p = 0.002). While these correlations were only observed in men, the rLTL of older women was negatively correlated with the number of thrombocytes (p = 0.015) in the same type of analysis. Among all older participants, 6% met the criteria to be categorized as 'anemic'; however, there was no association between anemia and rLTL. CONCLUSION: In the present study, we have detected isolated correlations between rLTL and hematological parameters; however, in all cases, rLTL explained only a small part of the variation of the analyzed parameters. In disagreement with some other studies showing similar data, we interpret the association between rLTL and some of the hematological parameters studied here to be at most marginal. This applies also to the role of rLTL in anemia, at least in the age group investigated here. Since BASE-II is yet another large cohort in which women have on average shorter telomeres than men, this finding will be addressed in the discussion with respect to the ongoing debate on gender differences in telomere length.