Endocrine factors, memory and perceptual capacities and aging in Asian men.

BACKGROUND: This cross-sectional study examined the associations of hormones and age with short-term memory and perceptual capacity in 472 healthy Asian men. METHODS: The symbol digit and digit span tests from the Swedish Performance Evaluation System were used to assess perceptual capacity and memory. Linear regression analyses with the stepwise method were carried out with the SPSS 21.0 package. RESULTS: Age was associated with lower dehydorepiandrosterone sulphate (DHEA/S), insulin growth factor-1 (IGF-1), thyroxine (T4), testosterone (T), bioavailable T (BioT) and error rate (Err) but higher glucose (GLU), sex hormone binding globulin (SHBG), estradiol (E2) and retention time (RT). High GLU was associated with higher error rate, longer RT of the perceptual capacity domain and shorter digit span (DSpan) of the short-term memory domain. Higher insulin-like growth factor binding protein-3 (BP3) was associated with longer DSpan. High cortisol (Cor) was associated with higher Err, while high DHEA/S was associated with shorter RT. All other hormones from the adrenal, somatotrophic and gonadal were not significantly associated with cognition. CONCLUSION: The findings suggest (1) a role for tighter control of blood glucose levels in cognitive decline with aging in men, (2) different hormones may be related to different parameters of cognition and "cognition" is not a unitary phenomenon and (3) further investigation of the potential for exogenous DHEA/S to slow cognitive decline in aging, especially as it relates to reaction time.

The association of metabolic syndrome and aging with cognition in Asian men.

BACKGROUND: The present cross-sectional study examined the associations of individual metabolic factors and age with the short-term memory and perceptual capacity in 472 healthy Asian men. METHODS: The symbol digit and digit span tests from the Swedish Performance Evaluation System were used to assess the perceptual capacity and memory cognitive domains. Linear regression with the stepwise method, and multivariate analyses of the General Linear Model with the Bonferroni correction for multiple comparisons were carried out with the SPSS 21.0 package. RESULTS: High blood pressure and HDL were not significantly associated with either short-term memory or perceptual capacity. Age and glucose level were negatively associated but regular physical exercise was positively associated with perceptual capacity. On the other hand, high triglyceride level (TG) was positively associated but high waist/height ratio was negatively associated with short-term memory. When men without any component of the metabolic syndrome (MetS) were compared with men with one, two or three or more components of MetS, no significant differences in cognitive performance were noted. CONCLUSION: Not all the metabolic factors were significantly associated with short-term memory or the perceptual capacity domains. Those that were did not show a sufficiently consistent pattern of association to support a role for MetS as a whole in cognitive decline with aging. It may not be meaningful to evaluate the association of MetS as a whole with cognition.

Associations of physical exercise as a lifestyle habit with lean and fat body mass and handgrip strength and age in Asian men.

BACKGROUND: We evaluated how the intensity of physical exercise as a lifestyle habit is associated with age, body composition and handgrip strength. METHODS: Total body composition was analyzed using DEXA. Exercise scores were derived from an administered questionnaire and the scoring was calculated using the Metabolic Equivalent of Task (MET). Handgrip strength was measured using a dynamometer. RESULTS: Age, independent of exercise intensity, was associated with declining lean mass, and handgrip strength and with increasing total body fat. A regular physical exercise regime of intensity greater than 1230 MET-min/week was associated with higher total lean mass and lean mass in the limbs, and handgrip strength and lower fat mass in the limbs. DISCUSSION: We have shown that age was associated with lower lean mass especially in the limbs and handgrip strength and higher total fat mass. Regular physical exercise as a lifestyle habit of any type and of sufficient intensity could help improve muscle strength in the limbs.

Association of age and physical exercise with bodyweight and body composition in Asian Chinese men.

BACKGROUND: The present study sought to examine the association between physical exercise as a lifestyle habit with anthropometric parameters and body composition and aging in men. METHODS: Intensity of exercise was scored as metabolic equivalent-min/week (MET-min/week) from data of the questionnaire, while anthropometric parameters and body composition were carried out by standard measuring instruments and dual-energy X-ray absorptiometry scanner, respectively. RESULTS: Age was associated with decreases in bodyweight, height, total lean mass and bone mass, but an increase in fat mass. The negative association of lean mass with age was predominantly due to the negative association of lean masses in the legs and arm, while the positive association of fat mass with age was primarily due to the positive association of fat masses in the trunk and abdomen. Exercise of intensity greater than 1000 MET-min/week was significantly associated with higher lean and bone masses and lower fat mass. The increase in lean mass was predominantly in the legs, while the decreases in fat mass were in the trunk and abdomen. CONCLUSION: The study showed that the high intensity of physical exercise, equivalent to greater than 1000 MET-min/week, is required to effect beneficial changes in the body composition. Hence, results from the study support the importance of promoting a lifestyle habit of exercise of sufficient intensity in order to mitigate the increase risks of sarcopenia and obesity and their attendant ill effects on health in men as they age.

Simultaneous measurement of serum testosterone and dihydrotestosterone by liquid chromatography-tandem mass spectrometry.

BACKGROUND: Recent reports have described inherent problems with androgen immunoassays compared with mass spectrometry analyses. METHODS: We developed a method for measuring serum testosterone (T) and 5alpha-dihydrotestosterone (DHT) simultaneously via liquid-liquid extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with positive-mode electrospray ionization. RESULTS: The DHT and T calibrators showed a linear response from 0.069 nmol/L to 34.4 nmol/L and 69.3 nmol/L, respectively. T interference in the DHT assay and vice versa were negligible. Within- and between-run imprecision values were <5% for both analytes. Percent recoveries of T and DHT spiked into samples at concentrations spanning the calibration curve were 100%-113% and 98%-107%, respectively. The lower limit of quantification was 0.069 nmol/L for both steroids. Serum T concentrations measured by LC-MS/MS were different from those obtained by RIA, especially at lower T concentrations. Serum DHT concentrations measured by LC-MS/MS were markedly lower than those generated by RIA because of the nonselectivity of the RIA without chromatography. The reference intervals (mean +/- 2 SDs) determined for T and DHT were 9.2-33.7 nmol/L and 0.47-2.65 nmol/L, respectively, for 113 healthy adult men and 0.33-2.02 nmol/L and 0.09-0.91 nmol/L, respectively, for 133 healthy premenopausal women. CONCLUSIONS: We have developed and validated a selective and precise method for simultaneous measurements of serum T and DHT that can be adopted for routine measurements of these androgens in health and disease in men and women.

Interactions among age, adiposity, bodyweight, lifestyle factors and sex steroid hormones in healthy Singaporean Chinese men.

AIM: To examine the inter-relationships among age, lifestyle factors, anthropometric parameters, percent body fat and steroid hormone parameters in 531 healthy Singaporean Chinese men aged between 29 and 72 years old. METHODS: Various lifestyle parameters were quantified through a survey, and testosterone (T), estradiol (E2), dehydroepiandrosterone sulphate (DHEAS) and sex hormone binding globulin (SHBG) were measured using established methods. Anthropometric parameters were collected and computed, and percent body fat (Siri) was measured using the DEXA scanner. RESULTS: SHBG, DHEAS, bioavailable-T (Bio-T), E2, Siri, Ht, W/H, W/Ht and work stress were independently correlated with age. Using multivariate analyses and adjusting for age and other related factors, exercise, smoking and alcohol consumption have positive impacts on androgen levels and body composition. However, black and green tea consumption was associated with negative effects on body composition and with higher levels of E2 and Free Estradiol Index (FEI). Men with shorter sleep duration had significantly lower T levels as compared to those with 6 h or more of nightly sleep. Higher T levels were associated with lower levels of adiposity and other indices of adiposity, whereas higher E2 levels were related to higher levels of adiposity. Men with higher DHEAS were significantly taller and heavier than those with low DHEAS levels. CONCLUSION: The study showed the close interactions among the gonadal/adrenal and metabolic compartments, with age being a key determinant in their interactions. Lifestyle factors such as exercise, smoking, sleeping and alcohol and tea consumption might play significantly roles in determining the status of health in men.

Differential impact of aging and gender on lipid and lipoprotein profiles in a cohort of healthy Chinese Singaporeans.

AIM: To evaluate the impact of age and gender on lipid and lipoprotein profiles and the burden of dyslipidemia in a cohort of healthy Chinese Singaporean. METHODS: A total of 1 775 healthy Chinese, 536 men and 1 239 women aged between 30 and 70 years old were involved in the present study. RESULTS: Gender differences in all lipid and lipoprotein levels were clearly evident. Singaporean Chinese men have significantly higher levels of total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol (LDL-C) and total cholesterol/high density lipoprotein-cholesterol (TC/HDL-C), and lower levels of HDL-C than women. Although lipid and lipoprotein levels in men did not change in the different age groups, those in women, especially TC, LDL-C and TC/HDL-C, were significantly higher in older women (> 50 years old) than corresponding levels in younger women (30-46 years old). Furthermore, TG was significantly correlated with lipids and lipoproteins differently in men and women. If 100 mg/dL of LDL-C were to be adopted as the therapeutic cut-off level, then the burden of care will be huge as approximately 90% of both Chinese men and women have LDL-C greater than 100 mg/dL. CONCLUSION: In light of the findings of the present study, we suggest that preventive measures to promote the reduction in risk of coronary heart disease (CHD) must address the high proportion of men and women with high LDL-C, and that these measures should take into account both the gender and age factors. For men, reduction of high cholesterol must start early in life, whereas for women, steps must be taken earlier to mitigate the anticipated sharp increase in risk, especially after menopause.

Effects of a brief action and coping planning intervention on completion of preventive exercises prescribed by a physiotherapist among people with knee pain.

OBJECTIVES: The present study aimed to test the efficacy of action and coping planning in promoting engagement with preventive exercises among a sample of people with knee pain. DESIGN: Experimental trial. METHODS: Individuals who presented to a physiotherapist with knee pain (N=373, 57% female; M age=31.54, SD=10.06, age range=18-69 years) completed two assessments separated by 14 days. At baseline, participants completed measures of severity of problems associated with the knee (e.g., pain, symptoms) and past behavior. Subsequently, participants were randomly assigned to an action and coping planning or control group. Two weeks later, participants retrospectively reported their preventive exercise behavior over the past 14 days. Analyses revealed that the experimental group reported a higher number of preventive exercise sessions over the 14day period when compared with the control group. RESULTS: Participants who planned action and coping strategies reported a greater frequency of completed preventive exercises over a 2-week period than people who did not. CONCLUSIONS: The results of this study underscore the importance of action and coping planning for the enactment of preventive exercises that are designed to manage or prevent knee pain.

Determinants of circulating insulin-like growth factor I and insulin-like growth factor binding protein 3 concentrations in a cohort of Singapore men and women.

Variation in the circulating concentrations of the insulin-like growth factor (IGF) system has been implicated in the etiology of chronic diseases including cancer (prostate, breast, colon, and lung), heart disease, type 2 diabetes, and osteoporosis. We searched for sociodemographic, anthropometric, reproductive, lifestyle, and dietary determinants of IGF-I and insulin-like growth factor binding protein (IGFBP) -3 serum concentrations. Serum samples were collected in a Singapore Chinese cohort with a mean age of 61 years. Subject information was assessed during an in-person interview. Radioimmunometrically measured IGF-I and IGFBP-3 concentrations were available for 312 men and 326 postmenopausal women ages 50 years or older. Mean IGF-I concentrations were 144 ng/ml and 121 ng/ml for men and women, respectively (gender difference, P < 0.0001), and mean IGFBP-3 concentrations were 3710 ng/ml and 4147 ng/ml for men and women, respectively (gender difference, P < 0.0001). IGF-I and IGFBP-3 decreased with age (P for trend <0.0001); the age-related decrease in the IGF-I:IGFBP-3 molar ratio was stronger in women than men. IGF-I concentrations were higher among physically inactive subjects and among women with an early age at menarche. Consumption of saturated fat was found to decrease, and intake of omega-3 polyunsaturated fatty acids and of dietary fiber was found to increase circulating IGFBP-3 concentrations. Intake of calcium from food and supplement was associated positively with circulating IGF-I, IGFBP-3, and molar ratio. Intake of soy was associated positively with IGF-I and molar ratio concentrations, but only in men. The results of this study lend additional support to the hypothesis that circulating IGF-I concentrations increase the risk of prostate, bladder, colorectal, and breast cancer.

The moderating impact of lifestyle factors on sex steroids, sexual activities and aging in Asian men.

The present study sought to evaluate the relative associations of exercise, sleep and other lifestyle habits with aging, sex hormones, percent body fat (%BF) and sexual activities in men living in the community. A better understanding of this complex interrelationship is important in helping the formulation of modalities for a holistic approach to the management of aging men. The results showed that age is a major determinant for many physiological parameters, including sleep, hormonal and metabolic parameters, some lifestyle factors and sexual activities. Testosterone (T), bioavailable testosterone (BioT) and dehydroepiandrosterone sulphate (DHEAS) concentrations decreased with age, while estradiol (E2), sex hormone-binding globulin (SHBG) and %BF increased with age. In addition, there exist intricate associations among hormonal and lifestyle factors, %BF and age. High-intensity exercise and longer duration of sleep were associated with higher concentrations of T and BioT. T was shown to be associated positively with men who were engaged in masturbation. DHEAS was associated with men wanting more sex and with good morning penile rigidity. Older Singaporean men tended to sleep for shorter duration, but exercised more intensely than younger men. Coital and masturbation frequencies decreased with age, and a significantly greater number of younger men were engaged in masturbation. Relationship between the partners is a key determinant of sexuality in men. It appears that T may have a limited, while dehydroepiandrosterone (DHEA) have a greater role than previously suggest, as a motivational signal for sexual function in men. Both biological and psychosocial factors interact with each other to influence sexual functions in men. Hence, a biopsychosocial approach may be more appropriate for a more lasting resolution to sexual dysfunctions in men.

Reexamination of testosterone, dihydrotestosterone, estradiol and estrone levels across the menstrual cycle and in postmenopausal women measured by liquid chromatography-tandem mass spectrometry.

Measuring serum androgen levels in women has been challenging due to limitations in method accuracy, precision sensitivity and specificity at low hormone levels. The clinical significance of changes in sex steroids across the menstrual cycle and lifespan has remained controversial, in part due to these limitations. We used validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays to determine testosterone (T) and dihydrotestosterone (DHT) along with estradiol (E2) and estrone (E1) levels across the menstrual cycle of 31 healthy premenopausal females and in 19 postmenopausal females. Samples were obtained in ovulatory women in the early follicular phase (EFP), midcycle and mid luteal phase (MLP). Overall, the levels of T, DHT, E2 and E1 in premenopausal women measured by LC-MS/MS were lower overall than previously reported with immunoassays. In premenopausal women, serum T, free T, E2, E1 and SHBG levels peaked at midcycle and remained higher in the MLP, whereas DHT did not change. In postmenopausal women, T, free T, SHBG and DHT were significantly lower than in premenopausal women, concomitant with declines in E2 and E1. These data support the hypothesis that the changes in T and DHT that occur across the cycle may reflect changes in SHBG and estrogen, whereas in menopause, androgen levels decrease. LC-MS/MS may provide more accurate and precise measurement of sex steroid hormones than prior immunoassay methods and can be useful to assess the clinical significance of changes in T, DHT, E2 and E1 levels in females.

Sleep, sex steroid hormones, sexual activities, and aging in Asian men.

This was a cross-sectional study to examine the different associations of age and sleep duration with sex steroid hormones and sexual activities in 531 Asian Chinese men aged between 29 and 72 years old. Sleep duration and sexual activities were evaluated through a self-administered questionnaire, and total testosterone (T), sex hormone-binding globulin (SHBG), estradiol (E2), and dehydroepiandrosterone sulfate (DHEAS) were measured by established immunoassay methods in a single blood sample collected between 8:00 and 11:00 am. Bioavailable T (BioT) was calculated using the Vermeulen formula. Age was a major determinant of sleep, sex steroid hormones, and sexual activities in men. BioT, DHEAS, coital frequency, masturbation, and sleep duration declined with age. On the other hand, SHBG and E2 increased with age. Sleep duration, independently of age, aerobic exercise, and body fat, was positively associated with T and BioT, but not with DHEAS, E2, or any of the sexual activities studied. Men who masturbated had higher levels of both T and BioT. DHEAS was significantly associated with coital frequency and desire for sex. The present study showed that besides age, sleep duration was associated with androgen concentrations in men, and thus the evaluation of sleep hygiene may be beneficial in the management of men with low androgen concentrations. DHEAS may be independently associated with some sexual functions in men.

Association between an intronic apolipoprotein E polymorphism and bone mineral density in Singaporean Chinese females.

INTRODUCTION: Apolipoprotein E (ApoE) is implicated in the pathogenesis of osteoporosis. OBJECTIVE: To investigate possible association of the non-classical APOE gene +113C/G (rs440446) intron 1 enhancer polymorphism with bone mineral density (BMD) in a homogeneous Chinese population in Singapore. METHODS: A total of 655 volunteers, males and females, aged between 31 and 72 years, from the public participated. BMD was measured using dual-energy X-ray absorptiometry and APOE +113C/G (rs440446) genotypes were determined by Sequenom MassARRAY system. To adjust for potential confounders, anthropometric, demographic, and lifestyle determinants were obtained, and serum lipids and E(2) were measured. RESULTS: The +113C/G (rs440446) polymorphism within the APOE gene was associated with BMD in Chinese Singaporean females only. Females with the heterozygous CG genotype were significantly associated with reduced total, lumbar spine, and femoral neck of hip BMD, after multilevel adjustment of confounders. The association was stronger in the spine than in the hip. When females were stratified according to WHO classification for osteoporosis, those with CG and GG genotypes had increased risk (OR 3.50 and 2.22, respectively) of developing osteopenia/osteoporosis in the lumbar spine. Serum lipids did not explain the influence of APOE +113 C/G (rs440446) on BMD. CONCLUSION: This study demonstrated an association between APOE +113C/G (rs440446) polymorphism with measures of BMD in Singaporean Chinese females.

Aging in Asia: a cultural, socio-economical and historical perspective.

Asia has about 60% of the world population and population aging is occurring more rapidly in Asia than in Western countries. The group aged 65 years and above will increase from 207 million in 2000 to 857 million in 2050, a staggering increase of 314%. The diversity in economic, demographic, religious, cultural and geo-political factors in Asia is unparalleled by any other continent, and is, in part, contributory to the rapid rise in population aging. By 2050, those under 15 years old will have shrunk from 30% in 2000 to 19%, while those aged 65 years and above will increase from 6% to 18%. In addition, the gender divide still persists with 100 elderly women to 70 elderly men. These projected demographic changes pose three major challenges: 1) how best to address the rising population of the group aged 65 years and above, 2) how to address the shrinking population of the young as well as the working adults, and 3) how to address the problems arising from the disproportionate increase in older women than men. From now to 2050, it will be expeditious for each country in Asia to look into ways of reversing the decline in total fertility rates (TFRs) and restore to replacement levels. If not, at least introduce measures to halt its free fall. Due to the complexity of factors that have influenced the fall in TFRs in Asia, it will be a daunting task to reverse this fall. There is no "single size fits all" solution to this complex problem. Research work in this short-term strategy in addressing the aging population is urgent. In the longer term, the East-West Centre have suggested four modalities, 1) establish policies and programmes that enhance traditional Asian systems of family support for the elderly; 2) introduce policy reform that encourages the elderly who are still capable of remaining in the work force; 3) create institutions and systems that support high levels of personal saving; and 4) formulate public programmes, including pension schemes and national healthcare systems. We need to work while there is time.

Are BMI and other anthropometric measures appropriate as indices for obesity? A study in an Asian population.

We have examined the relationships between percentage of body fat (PBF) and risk factors for cardiovascular disease and insulin resistance and how good body mass index (BMI) and other anthropometric measures are as indices of obesity. High PBF levels were associated with increased risk of cardiovascular disease and insulin resistance. The World Health Organization BMI of 30 kg/m(2) for obesity has low sensitivity, 6.7% and 13.4% for men and women, respectively. For every obese man and woman identified, 6.7 and 1.76 times nonobese men and women, respectively, will be misclassified as obese. With the locally established BMI cutoff point for obesity of 27 kg/m(2) for men and 25 kg/m(2) for women, the sensitivity was improved to 46.7% and 60.8%, respectively. For every obese man and woman identified, 3.76 and 1.64 times nonobese men and women, respectively, will be misclassified as obese. None of the other anthropometric indices was better than the locally established BMIs. We showed that the BMIs for obesity for our local men and women are different. These BMIs were most precise among all indices studied. However, they still lead to high false-positive rates. For more effective management of the problem of obesity, we need to develop more precise, simple, and cost-effective methods for the measurement of PBF.