Cardiovascular risk factors and hyperinsulinemia in elderly men: the Honolulu Heart Program

Dysregulation of hepatic metabolism with obesity: factors influencing glucose and lipid metabolism

The liver is a key metabolic organ that undertakes a multitude of physiological processes over the course of a day, including intrahepatic lipid and glucose metabolism which plays a key role in the regulation of systemic lipid and glucose concentrations. It serves as an intermediary organ between exogenous (dietary) and endogenous energy supply to extrahepatic organs. Thus, perturbations in hepatic metabolism can impact widely on metabolic disease risk. For example, the accumulation of intra-hepatocellular TAG (IHTG), for which adiposity is almost invariably a causative factor may result in dysregulation of metabolic pathways. Accumulation of IHTG is likely due to an imbalance between fatty acid delivery, synthesis and removal (via oxidation or export as TAG) from the liver; insulin plays a key role in all of these processes.

Anthropometric Obesity Indices were Stronger than CT-Based Indices in Associations with Carotid Intima-Media Thickness in Japanese Men

AIM

Computed tomography (CT) can directly provide information on body compositions and distributions, compared to anthropometric indices. It has been shown that various obesity indices are associated with carotid intima-media thickness (IMT). However, whether CT-based obesity indices are stronger than anthropometric indices in association with atherosclerosis remains to be determined in a general population.

METHODS

We cross-sectionally assessed carotid IMT using ultrasound in 944 community-dwelling Japanese men free of stroke and myocardial infarction. CT image at the L4-L5 level was obtained to compute areas of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). Anthropometric measures assessed included body mass index (BMI), waist circumference, and waist-to-hip ratio. Using multivariable linear regression, slopes of IMT per 20^th to 80^th percentile of each index were compared. We also compared the slope of index with simultaneous adjustment for BMI in the same model.

RESULTS

Areas of VAT and SAT were positively associated with IMT, but not stronger than those of anthropometric indices in point estimates. Among all obesity indices, BMI was strongest in association with IMT after adjusting for age and lifestyle factors or further adjusting for metabolic factors. In simultaneous adjustment models, BMI, but not CT-based indices, remained significant and showed the strongest association.

CONCLUSIONS

In community-dwelling Japanese men, anthropometric obesity indices, BMI in particular, were more strongly associated with carotid atherosclerosis than CT-based obesity indices. The association of general obesity with carotid atherosclerosis was strong and adding CT-based obesity measure did not considerably influence in the association.

Circulating betatrophin is associated with insulin resistance in humans: cross-sectional and interventional studies in vivo and in vitro

Betatrophin has a closely relationship with metabolism. However, its effect on metabolism disorder remains unclear. This study was comprised of a series of cross-sectional and interventional studies in vivo and vitro. PCOS women with IR and healthy women were recruited from the general population and outpatients. Plasma betatrophin levels were measured with ELISA. Insulin sensitivity was assessed with EHC. Gene expressions at mRNA and protein levels were determined with RT-PCR and Western blotting. Influences of insulin, metformin, rosiglitazone and over- or knockdown-expression of betatrophin were analyzed ex vivo. Our results indicated that IR women had higher betatrophin levels compared with the controls. Circulating betatrophin was positively correlated with BMI, WHR, Fat%, triglyceride, total cholesterol, LDL-C, AUC_glucose and AUC_insulin, luteinizing Hormone, FAI and HOMA-IR but negatively with M-value. Metformin treatment in PCOS women with IR led to a reduction of betatrophin levels. Insulin stimulation in hepatocytes increased betatrophin expression. Metformin or rosiglitazone led to a reduction of betatrophin expression in insulin-stimulated hepatocytes. In hepatocytes/macrophages co-culture systems, betatrophin expression was significantly increased, whereas this increase was eliminated by rosiglitazone. In hepatocytes, overexpression and knockdown of betatrophin decreased or increased insulin-stimulated insulin receptor, protein kinase B and insulin receptor substrate-1 phosphorylation respectively. Serum from metformin-treated women with IR decreased betatrophin expression and reinforced insulin signals. Thus, the present study provides the in vivo and in vitro evidence, suggesting that there is a cell cross-talking between hepatocytes with macrophages for the regulating betatrophin and it may be a useful marker for IR and metabolic disorders.

Glycated Hemoglobin, Fasting Insulin and the Metabolic Syndrome in Males. Cross-Sectional Analyses of the Aragon Workers' Health Study Baseline

Background and Aims

Glycated hemoglobin (HbA1c) is currently used to diagnose diabetes mellitus, while insulin has been relegated to research. Both, however, may help understanding the metabolic syndrome and profiling patients. We examined the association of HbA1c and fasting insulin with clustering of metabolic syndrome criteria and insulin resistance as two essential characteristics of the metabolic syndrome.

Methods

We used baseline data from 3200 non-diabetic male participants in the Aragon Workers' Health Study. We conducted analysis to estimate age-adjusted odds ratios (ORs) across tertiles of HbA1c and insulin. Fasting glucose and Homeostatic model assessment - Insulin Resistance were used as reference. Here we report the uppermost-to-lowest tertile ORs (95%CI).

Results

Mean age (SD) was 48.5 (8.8) years and 23% of participants had metabolic syndrome. The ORs for metabolic syndrome criteria tended to be higher across HbA1c than across glucose, except for high blood pressure. Insulin was associated with the criteria more strongly than HbA1c and similarly to Homeostatic model assessment - Insulin Resistance (HOMA-IR). For metabolic syndrome, the OR of HbA1c was 2.68, of insulin, 11.36, of glucose, 7.03, and of HOMA-IR, 14.40. For the clustering of 2 or more non-glycemic criteria, the OR of HbA1c was 2.10, of insulin, 8.94, of glucose, 1.73, and of HOMA-IR, 7.83. All ORs were statistically significant. The areas under the receiver operating characteristics curves for metabolic syndrome were 0.670 (across HbA1c values) and 0.770 (across insulin values), and, for insulin resistance, 0.647 (HbA1c) and 0.995 (insulin). Among non-metabolic syndrome patients, a small insulin elevation identified risk factor clustering.

Conclusions

HbA1c and specially insulin levels were associated with metabolic syndrome criteria, their clustering, and insulin resistance. Insulin could provide early information in subjects prone to develop metabolic syndrome.

Hyperinsulinemic syndrome: the metabolic syndrome is broader than you think

BACKGROUND

Type 2 diabetes mellitus (T2DM) is characterized by hyperinsulinemia. In 2011 we showed that gastric bypass (RYGB) corrects these high levels even though insulin resistance remains high, ie, the operation "dissociates" hyperinsulinemia from insulin resistance. RYGB produces reversal of T2DM along with other diseases associated with the metabolic syndrome. This observation led us to examine whether these illnesses also were characterized by hyperinsulinemia.

METHODS

A systematic review was performed to determine whether hyperinsulinemia was present in disorders associated with the metabolic syndrome. We reviewed 423 publications. 58 were selected because of appropriate documentation of insulin measurements. Comparisons were based on whether the studies reported patients as having increased versus normal insulin levels for each metabolic disorder.

RESULTS

The presence (+) or absence (-) of hyperinsulinemia was documented in these articles as follows: central obesity (4+ vs 0-), diabetes (5+ vs 0-), hypertension (9+ vs 1-), dyslipidemia (2+ vs 0-), renal failure (4+ vs 0-), nonalcoholic fatty liver disease (5+ vs 0-), polycystic ovary syndrome (7+ vs 1-), sleep apnea (7+ vs 0-), certain cancers (4+ vs 1-), atherosclerosis (4+ vs 0-), and cardiovascular disease (8+ vs 0-). Four articles examined insulin levels in the metabolic syndrome as a whole (4+ vs 0-).

CONCLUSION

These data document that disorders linked to the metabolic syndrome are associated with high levels of insulin, suggesting that these diseases share a common etiology that is expressed by high levels of insulin. This leads us to propose the concept of a "hyperinsulinemic syndrome" and question the safety of insulin as a chronic therapy for patients with T2DM.

Shorter men live longer: association of height with longevity and FOXO3 genotype in American men of Japanese ancestry

Objectives

To determine the relation between height, FOXO3 genotype and age of death in humans.

Methods

Observational study of 8,003 American men of Japanese ancestry from the Honolulu Heart Program/Honolulu-Asia Aging Study (HHP/HAAS), a genetically and culturally homogeneous cohort followed for over 40 years. A Cox regression model with age as the time scale, stratified by year of birth, was used to estimate the effect of baseline height on mortality during follow-up. An analysis of height and longevity-associated variants of the key regulatory gene in the insulin/IGF-1 signaling (IIS) pathway, FOXO3, was performed in a HHP-HAAS subpopulation. A study of fasting insulin level and height was conducted in another HHP-HAAS subpopulation.

Results

A positive association was found between baseline height and all-cause mortality (RR = 1.007; 95% CI 1.003–1.011; P = 0.002) over the follow-up period. Adjustments for possible confounding variables reduced this association only slightly (RR = 1.006; 95% CI 1.002–1.010; P = 0.007). In addition, height was positively associated with all cancer mortality and mortality from cancer unrelated to smoking. A Cox regression model with time-dependent covariates showed that relative risk for baseline height on mortality increased as the population aged. Comparison of genotypes of a longevity-associated single nucleotide polymorphism in FOXO3 showed that the longevity allele was inversely associated with height. This finding was consistent with prior findings in model organisms of aging. Height was also positively associated with fasting blood insulin level, a risk factor for mortality. Regression analysis of fasting insulin level (mIU/L) on height (cm) adjusting for the age both data were collected yielded a regression coefficient of 0.26 (95% CI 0.10–0.42; P = 0.001).

Conclusion

Height in mid-life is positively associated with mortality, with shorter stature predicting longer lifespan. Height was, moreover, associated with fasting insulin level and the longevity genotype of FOXO3, consistent with a mechanistic role for the IIS pathway.

Late-life factors associated with healthy aging in older men

OBJECTIVES

To identify potentially modifiable late-life biological, lifestyle, and sociodemographic factors associated with overall and healthy survival to age 85.

DESIGN

Prospective longitudinal cohort study with 21 years of follow-up (1991-2012).

SETTING

Hawaii Lifespan Study.

PARTICIPANTS

American men of Japanese ancestry (mean age 75.7, range 71-82) without baseline major clinical morbidity and functional impairments (N = 1,292).

MEASUREMENTS

Overall survival and healthy survival (free from six major chronic diseases and without physical or cognitive impairment) to age 85. Factors were measured at late-life baseline examinations (1991-1993).

RESULTS

Of 1,292 participants, 1,000 (77%) survived to 85 (34% healthy) and 309 (24%) to 95 (<1% healthy). Late-life factors associated with survival and healthy survival included biological (body mass index, ankle-brachial index, cognitive score, blood pressure, inflammatory markers), lifestyle (smoking, alcohol use, physical activity), and sociodemographic factors (education, marital status). Cumulative late-life baseline risk factor models demonstrated that age-standardized (at 70) probability of survival to 95 ranged from 27% (no factors) to 7% (≥ 5 factors); probability of survival to 100 ranged from 4% (no factors) to 0.1% (≥ 5 factors). Age-standardized (at 70) probability of healthy survival to 90 ranged from 4% (no factors) to 0.01% (≥ 5 factors). There were nine healthy survivors at 95 and one healthy survivor at 100.

CONCLUSION

Several potentially modifiable risk factors in men in late life (mean age 75.7) were associated with markedly greater probability of subsequent healthy survival and longevity.

Insulin and sex interactions in older adults with mild cognitive impairment

Alzheimer's disease (AD) and other dementias are likely preceded by a protracted preclinical state. Thus, identification of biomarkers that signal potential points of intervention during this prodromal phase (during which patients are largely able to compensate for their cognitive deficits) is of paramount importance. Insulin is a pancreatic hormone with potent central nervous system effects, and insulin dysregulation has been implicated in the pathogenesis of both AD and vascular dementia. The aim of the current study was to determine whether circulating insulin differs as a function of mild cognitive impairment (MCI) diagnosis, and whether this relationship is mediated by sex and apolipoprotein E (APOE) genotype. A sample of 549 nondemented participants aged 65 and over from the Adult Changes in Thought community-based cohort underwent cognitive testing and blood draw to determine fasting levels of plasma insulin. Subjects were categorized as having normal cognitive functioning, amnestic MCI, or nonamnestic MCI. Results showed that the relationship between insulin and diagnostic category is moderated by sex, such that men with nonamnestic or amnestic MCI have higher fasting plasma insulin than cognitively normal men, while women with amnestic MCI have lower fasting plasma insulin than cognitively normal women. Exploratory analyses suggest that APOE ε4 genotype may further influence the relationship between sex and insulin. Future research will help determine whether insulin dysregulation results in differential effects on vascular function and AD pathology as a function of sex and/or APOE genotype.

Glucose tolerance in pregnancy and the long-term risk of cardiovascular disease

BACKGROUND

Studies demonstrate an association between high but non-diabetic blood glucose levels and cardiovascular morbidity and mortality. Pregnancy alters glucose metabolism and results in a continuum of glucose tolerance, it is not known whether this continuum is associated with a continuum of risk of CVD in later life.

OBJECTIVES

To examine the long-term risk of CVD associated with the continuum of maternal glucose tolerance.

PARTICIPANTS

Nine hundred and seventeen participants assessed during pregnancy and followed over 20 years.

MEASUREMENTS

Smoking behaviour, BMI at index pregnancy and follow-up, and gestational HbA1c.

MAIN OUTCOME

Requiring medication for hypertension and CVD, and hospital admissions for CVD as ascertained by record linkage over 20-year period.

RESULTS

Fifty-one women had a history of CVD, 85 women had hypertension and 17 women (2.3%) were admitted for CVD. There was a significant increase in the risk for CVD, hypertension and hospitalisation for CVD across the quartiles of gestational HbA1c after adjustment for known risk factors. This increased risk reached statistical significance in the highest quartile although confidence intervals were wide.

CONCLUSION

Sub-clinical HbA1c during pregnancy was associated with a dose-related increase in the presence of medication and hospital admission for CVD. The magnitude of these effects is of note.

Impact of metformin and rosiglitazone treatment on glucose transporter 4 mRNA expression in women with polycystic ovary syndrome

OBJECTIVE

The insulin-resistant state of the polycystic ovary syndrome (PCOS) was found to be associated with a decreased glucose transporter GLUT4 expression in the insulin target tissues. This study was performed to explore whether the well-known clinical, hormonal and metabolic efficacy of metformin or rosiglitazone treatment is reflected in the modulation of adipocyte GLUT4 mRNA expression in patients with PCOS.

METHODS

We enrolled 35 women with PCOS. They received either metformin or rosiglitazone for 6 months. A history, blood samples for the measurement of androgens and s.c. adipose tissue samples were taken at baseline and end point. Quantification of GLUT4 mRNA expression in adipose tissue was performed using real-time quantitative PCR. Homeostasis model assessment (HOMA(IR)) score calculation was applied as a measure for insulin resistance (IR).

RESULTS

GLUT4 mRNA expression in adipose tissue increased significantly in both groups (P<0.001). The increase was more pronounced in the rosiglitazone group (P=0.040). There was a statistically significant improvement of HOMA(IR) in both groups (P=0.008). After treatment, frequencies of menstrual bleeding were significantly higher (P<0.001) and serum total testosterone levels significantly lower in both groups (P=0.001).

CONCLUSIONS

A 6-month therapy with insulin sensitizers resulted in marked improvement in adipose tissue GLUT4 mRNA expression in PCOS patients, rosiglitazone being more effective when compared with metformin. The augmentation of the insulin signal transduction was accompanied by a significant improvement of HOMA(IR), menstrual pattern and androgen profile.

Asian adolescents have a higher trunk:peripheral fat ratio than Whites

Body fat, especially in the upper body, has been associated with increased risk of chronic disease among adults. Factors associated with these traits among ethnically diverse populations are not well studied. We examined factors influencing body fat and weight among Asian and White adolescent girls from the female adolescent maturation longitudinal study (initial exam plus 2-y follow-up examination) in Hawaii. The objective of this study was to identify and compare influences on and differences in body size and fat distribution among Asian and White adolescent girls. Subjects were identified among age-eligible members of a large HMO. Of the 214 girls recruited for Exam 1, 107 girls returned for Exam 2. The girls' age, ethnicity, a 3-d diet record, and physical activity recall were obtained by questionnaire at both times, and Tanner pubic hair stage and anthropometry were clinically measured by trained staff at both exams. The ethnic proportion of the study sample was 57% Asian and 43% White. Each girl's ethnicity was based on the ethnic proportion of each biologic parent. The percentage of body fat was measured by Lunar Prodigy dual energy X-ray absorptiometry (DXA) at the follow-up exam only. Among various measures of skeletal size and adiposity, only leg length (inversely) and DXA trunk:peripheral fat ratio (directly) were associated with proportion of Asian ethnicity, after adjusting for age, Tanner pubic hair stage, physical activity, and energy intake. In a multivariate analysis focusing on the trunk:peripheral fat ratio, this measure of central obesity was positively associated with proportion of Asian ethnicity (P = 0.001) and bi-iliac breadth (P = 0.002), and negatively associated with birth weight (P = 0.021), after adjustment for Tanner pubic hair stage, physical activity, energy intake, biacromial breadth, and height. In conclusion, Asian adolescents have a higher trunk:peripheral fat ratio than Whites. Adolescent bi-iliac breadth (positively) and birthweight (negatively) are associated with more body fat on the trunk vs. periphery during adolescence.

Insulin secretion, sensitivity, and metabolic profile of young healthy offspring of hypertensive parents

Hyperinsulinemia and insulin resistance are commonly observed in essential hypertension, which is part of the metabolic syndrome. The aim of this study was to examine whether insulin secretion abnormalities or alterations in insulin sensitivity and glucose tolerance are also present in healthy men, offspring of patients with essential hypertension. Twelve young (27 +/- 3.6 years), lean normotensive offspring were compared with 14 age-, sex-, and body mass index (BMI)-matched controls without a family history of hypertension, diabetes mellitus, and coronary heart disease. We studied glucose tolerance, insulin secretion, and sensitivity using 10-hour hyperglycemic and 10-hour hyperinsulinemic-euglycemic clamps (HIC). Glucose tolerance was comparable in the offspring and controls. However, the offspring had higher insulin and C-peptide levels during the hyperglycemic clamp (HGC) compared with controls (P <.05). There was no difference in the early phase of insulin secretion between the groups. The insulin sensitivity index (glucose infusion rate/serum insulin) was significantly lower in the offspring during both clamps. Moreover, the offspring had higher systolic (P <.001) and diastolic (P <.001) blood pressure and had higher serum cholesterol (P <.01) and triglyceride (P <.05) levels. Apparently healthy, young, lean individuals with a genetic predisposition to essential hypertension and with normal glucose tolerance had higher insulin secretion and lower insulin sensitivity than controls. These abnormalities, together with higher blood pressure and altered lipid metabolism, may play a role in the development of hypertension and an increased risk of cardiovascular morbidity and mortality in these individuals.

Body mass index and hospitalization in the elderly

OBJECTIVES

To explore the association between body mass index (BMI) and hospital usage in the elderly.

DESIGN

Retrospective cohort study.

SETTING

Medicare Current Beneficiary Survey (1992-94).

PARTICIPANTS

Eight thousand seven hundred fifty-four noninstitutionalized individuals aged 65 to 100 without cancer at baseline and with available data on height and weight.

MEASUREMENTS

BMI categorized by quintiles and by the 1998 National Heart Lung and Blood Institute (NHLBI) BMI classification. Poisson regression was used for multivariate analyses relating BMI to number of hospitalizations, adjusting for sex, age, smoking status, and heart disease.

RESULTS

During 20464 years of observation, 1199 individuals had 4096 hospitalizations and 34190 hospital days. Individuals in the lowest BMI quintile had a higher risk of hospitalization than those in the middle BMI quintile (RR=1.22; 95% confidence interval=1.1-1.4); stratified analyses by age revealed that this association remained for individuals aged 65 to 75. Using the NHLBI classification, underweight, overweight, mild obesity, and moderate to severe obesity were related to higher risk of hospitalizations than normal BMI in individuals aged 65 to 75. In individuals older than 75, underweight, overweight, and mild obesity were not related to a higher risk of hospitalizations. Moderate to severe obesity was related to a higher risk of hospitalization in individuals aged 75 to 89, which represented only 1.5% of the sample.

CONCLUSION

BMI is not a predictor of hospitalization for most individuals aged 75 and older.

The American Diabetes Association and World Health Organization classifications for diabetes: their impact on diabetes prevalence and total and cardiovascular disease mortality in elderly Japanese-American men

OBJECTIVE

To compare the prevalence of diabetes according to the American Diabetes Association (ADA) and World Health Organization (WHO) classifications in a sample of elderly Japanese-American men; to examine the association with total and cardiovascular mortality by diabetes status using both classifications; and to determine whether the fasting or 2-h glucose measurement is a stronger predictor of adverse outcomes.

RESEARCH DESIGN AND METHODS

Examinations given from 1991 to 1993 in the Honolulu Heart Program were used as baseline for these analyses. Subjects were 71-93 years of age at that time and were followed for total and cardiovascular disease mortality for up to 7 years.

RESULTS

A total of approximately 66% of individuals who had diabetes by WHO criteria were missed when the ADA definition was used. The relative risks of total and cardiovascular mortality for those with versus those without diabetes were similar for both definitions; however, when fasting and postload glucose measures were analyzed as continuous variables, the 2-h measurement was a superior predictor and was independent of fasting glucose. In contrast, fasting glucose was not an independent predictor of these outcomes in the presence of the 2-h measurement.

CONCLUSIONS

The prevalence of glucose metabolism abnormalities was very high among elderly Japanese-American men. The WHO classification was superior to the ADA classification in identification of subjects at high risk for adverse outcomes. Therefore, we conclude that the 2-h glucose measurement is valuable and should be retained in epidemiologic studies.

Insulin resistance, polycystic ovary syndrome, and type 2 diabetes mellitus

OBJECTIVE

To review the definition and prevalence of two insulin resistance (IR)-associated phenotypes, polycystic ovary syndrome (PCOS) and type 2 diabetes mellitus, as well as the risk and nature of their simultaneous presentation.

DESIGN

Review of published literature.

RESULT(S)

Insulin resistance affects between 10% and 25% of the general population. Two common disorders frequently associated with IR are PCOS, affecting 4% to 6% of reproductive-aged women, and type 2 diabetes mellitus, which is observed in about 2% to 6% of similarly aged women. Overall, about 50% to 70% of women with PCOS and 80% to 100% of patients with type 2 diabetes mellitus have variable degrees of IR. Insulin resistance and its secondary hyperinsulinemia appear to underlie many of the endocrine features of PCOS in a large proportion of such patients. The risk of type 2 diabetes mellitus among PCOS patients is 5- to 10-fold higher than normal. In turn, the risk of PCOS among reproductive-aged type 2 diabetes mellitus patients appears to be similarly increased.

CONCLUSION(S)

It remains to be determined whether PCOS and type 2 diabetes mellitus represent no more than different clinical manifestations of the same IR syndrome, with their phenotypic differences due to the presence or absence of a coincidental genetic defect at the level of the ovary or pancreas, respectively, or representing the result of etiologically different subtypes of IR syndromes.

Cholesterol and all-cause mortality in elderly people from the Honolulu Heart Program: a cohort study

BACKGROUND

A generally held belief is that cholesterol concentrations should be kept low to lessen the risk of cardiovascular disease. However, studies of the relation between serum cholesterol and all-cause mortality in elderly people have shown contrasting results. To investigate these discrepancies, we did a longitudinal assessment of changes in both lipid and serum cholesterol concentrations over 20 years, and compared them with mortality.

METHODS

Lipid and serum cholesterol concentrations were measured in 3572 Japanese/American men (aged 71-93 years) as part of the Honolulu Heart Program. We compared changes in these concentrations over 20 years with all-cause mortality using three different Cox proportional hazards models.

FINDINGS

Mean cholesterol fell significantly with increasing age. Age-adjusted mortality rates were 68.3, 48.9, 41.1, and 43.3 for the first to fourth quartiles of cholesterol concentrations, respectively. Relative risks for mortality were 0.72 (95% CI 0.60-0.87), 0.60 (0.49-0.74), and 0.65 (0.53-0.80), in the second, third, and fourth quartiles, respectively, with quartile 1 as reference. A Cox proportional hazard model assessed changes in cholesterol concentrations between examinations three and four. Only the group with low cholesterol concentration at both examinations had a significant association with mortality (risk ratio 1.64, 95% CI 1.13-2.36).

INTERPRETATION

We have been unable to explain our results. These data cast doubt on the scientific justification for lowering cholesterol to very low concentrations (<4.65 mmol/L) in elderly people.

Ethnic issues in the epidemiology of childhood obesity

Childhood obesity may be seen as a marker for high-risk dietary and physical inactivity practices. Recent increases in the prevalence of overweight and obesity among American children are not limited to one age, gender, or ethnic group, which suggests that unique behaviors of the members of various racial or ethnic subgroups of the population are unlikely to be the major contributing factors. Rather, it seems that environmental changes promoting increased energy intake and decreased energy output are occurring and have widespread impact on children from various backgrounds. Although no ethnic group is immune from the current shift in energy balance, differential rates of overweight seem to exist among ethnic groups. National probability samples of African-American, Hispanic, and white children in the United States provide clear evidence that white children are at lower risk for childhood overweight than are African-American or Hispanic children. Of concern is the lack of national data on the prevalence of overweight and obesity for Native-American and Asian-American groups. Also of concern is the aggregation of racial and ethnic subgroups, which may render prevalence rates meaningless. This possibility is clearly true with some surveys of weight status that combine diverse populations, such as Asians and Pacific Islanders, into one group. The high rates of obesity in African-American, Hispanic, and Native-American children are of concern. Although parental SES is associated inversely with childhood obesity among whites, higher SES does not seem to protect African-American and Hispanic children against obesity. In these groups, childhood obesity does not seem to be associated significantly with parental income and education. Health consequences of childhood obesity include a higher prevalence of type 2 diabetes and an increased risk for adverse levels of lipids, lipoproteins, and blood pressure. The effects of recently reported unprecedented levels of childhood overweight on subsequent risk for obesity in middle age are not known until future longitudinal data can be collected. It seems likely, however, that future health consequences of current early and severe childhood obesity will be staggering. Funding for adult follow-up of longitudinal studies of high-risk African American, Hispanic, and Native-American children is needed urgently to provide information on the long-term effects of childhood obesity. Halting the obesity epidemic is a formidable task, but the success in recent decades of drastically reducing childhood undernutrition offers hope and should spur similar action and leadership efforts. Promotion of efforts to reduce excess caloric intake with efforts to increase energy expenditure should receive paramount attention in the design of health programs. Given the relatively few published obesity-prevention and treatment studies that are designed to address specific cultural issues, it is important to promote the development of culturally appropriate intervention strategies that are shown to be effective among youth of diverse backgrounds. Although the dietary and activity goals will be similar, parental, family, and community messages and techniques grounded in cultural traditions and norms will be different for each ethnic group. This approach is crucial in the United States, a country with an increasingly diverse population.

Lifestyle factors and stroke risk: exercise, alcohol, diet, obesity, smoking, drug use, and stress

Various lifestyle factors have been associated with increasing the risk of stroke. These include lack of exercise, alcohol, diet, obesity, smoking, drug use, and stress. Guidelines endorsed by the Centers for Disease Control and Prevention and the National Institutes of Health recommend that Americans should exercise for at least 30 minutes of moderately intense physical activity on most, and preferably all, days of the week. Recent epidemiologic studies have shown a U-shaped curve for alcohol consumption and coronary heart disease mortality, with low-to-moderate alcohol consumption associated with lower overall mortality. High daily dietary intake of fat is associated with obesity and may act as an independent risk factor or may affect other stroke risk factors such as hypertension, diabetes, hyperlipidemia, and cardiac disease. Homocysteine is another important dietary component associated with stroke risk, while other dietary stroke risk factors are thought to be mediated through the daily intake of several vitamins and antioxidants. Smoking, especially current smoking, is a crucial and extremely modifiable independent determinant of stroke. Despite the obstacles to the modification of lifestyle factors, health professionals should be encouraged to continue to identify such factors and help improve our ability to prevent stroke.

Orthostatic hypotension predicts mortality in elderly men: the Honolulu Heart Program

BACKGROUND

Population-based data are unavailable concerning the predictive value of orthostatic hypotension on mortality in ambulatory elderly patients, particularly minority groups.

METHODS AND RESULTS

With the use of data from the Honolulu Heart Program's fourth examination (1991 to 1993), orthostatic hypotension was assessed in relation to subsequent 4-year all-cause mortality among a cohort of 3522 Japanese American men 71 to 93 years old. Blood pressure was measured in the supine position and after 3 minutes of standing, with the use of standardized methods. Orthostatic hypotension was defined as a drop in systolic blood pressure (SBP) of >/=20 mm Hg or in diastolic blood pressure of >/=10 mm Hg. Overall prevalence of orthostatic hypotension was 6.9% and increased with age. There was a total of 473 deaths in the cohort over 4 years; of those who died, 52 had orthostatic hypotension. Four-year age-adjusted mortality rates in those with and without orthostatic hypotension were 56.6 and 38.6 per 1000 person-years, respectively. With the use of Cox proportional hazards models, after adjustment for age, smoking, diabetes mellitus, body mass index, physical activity, seated systolic blood pressure, antihypertensive medications, hematocrit, alcohol intake, and prevalent stroke, coronary heart disease and cancer, orthostatic hypotension was a significant independent predictor of 4-year all-cause mortality (relative risk 1.64, 95% CI 1.19 to 2.26). There was a significant linear association between change in systolic blood pressure from supine position to standing and 4-year mortality rates (test for linear trend, P<0.001), suggesting a dose-response relation.

CONCLUSIONS

Orthostatic hypotension is relatively uncommon, may be a marker for physical frailty, and is a significant independent predictor of 4-year all-cause mortality in this cohort of elderly ambulatory men.