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Biomedical subjects

K M Narayan

Publications and source records attributed to K M Narayan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Relation of birth weight to lean and fat thigh tissue in young men.

BACKGROUND: Birth weight is positively associated with body mass index (BMI, kg/m2) in later life, but is inversely associated with cardiovascular risk. To understand this paradox, we examined the relationships between birth weight, adult BMI, and estimations of lean and fat tissue in young men. METHODS: From 192 applicants for military service (ages 17-22 y, mean BMI 23.2 kg/m2) with known birth weights we measured the circumference and anterior skinfold thickness at midthigh to estimate thigh muscle+bone area and subcutaneous fat area. Linear regression models including birth weight as the independent variable were adjusted for race and adult height. RESULTS: BMI was linearly associated with birth weight (standardized regression coefficient, [SRC]=+0.27; P=0.0004), as was the thigh muscle+bone area (SRC=+0.22; P=0.0029), but not the thigh subcutaneous fat area (SRC=+0.13; P=0.086). The BMI-birth weight association was reduced by 68% when the regression model was further adjusted for thigh muscle+bone area. Separate adjustment for thigh subcutaneous fat, however, reduced the BMI-birth weight association by only 30%. Waist circumference was also associated with birth weight (SRC=+0.24; P=0.0014), sagittal abdominal diameter was weakly associated (SRC=+0.17; P=0.028), but waist/thigh ratio and abdominal diameter index were not associated with birth weight. INTERPRETATION: The larger BMI associated with higher birth weight may reflect increments in lean tissue more than increments in fat. Birth weight's influence on lean tissue is observed in the thigh and, among fit young men, perhaps at the waist. Increased muscularity in young men may partly explain the cardiovascular benefit in middle age ascribed to higher birth weight.

Abdomen↗
PubMed2000

Type 2 diabetes among North American children and adolescents: an epidemiologic review and a public health perspective.

OBJECTIVES: To review the magnitude, characteristics, and public health importance of type 2 diabetes in North American youth. RESULTS: Among 15- to 19-year-old North American Indians, prevalence of type 2 diabetes per 1000 was 50.9 for Pima Indians, 4.5 for all US American Indians, and 2.3 for Canadian Cree and Ojibway Indians in Manitoba. From 1967-1976 to 1987-1996, prevalence increased 6-fold for Pima Indian adolescents. Among African Americans and whites aged 10 to 19 years in Ohio, type 2 diabetes accounted for 33% of all cases of diabetes. Youth with type 2 diabetes were generally 10 to 19 years old, were obese and had a family history of type 2 diabetes, had acanthosis nigricans, belonged to minority populations, and were more likely to be girls than boys. At follow-up, glucose control was often poor, and diabetic complications could occur early. CONCLUSIONS: Type 2 diabetes is an important problem among American Indian and First Nation youth. Other populations have not been well studied, but cases are now occurring in all population groups, especially in ethnic minorities. Type 2 diabetes among youth is an emerging public health problem, for which there is a great potential to improve primary and secondary prevention.

Adolescent↗
PubMed2000

Screening for type 2 diabetes.

Definitive studies of the effectiveness of screening for type 2 diabetes are currently not available. RCTs would be the best means to assess effectiveness, but several barriers prevent these studies from being conducted. Prospective observational studies may characterize some of the benefits of screening by creating screened and unscreened groups for comparison. The availability of better data systems and health services research techniques will facilitate such comparisons. Unfortunately, the interpretation of the results of such studies is extremely problematic. Several screening tests have been evaluated. Risk assessment questionnaires have generally performed poorly as stand-alone tests. Screening with biochemical tests performs better. Venous and capillary glucose measurements may perform more favorably than urinary glucose or HbA(1c) measurements, and measuring postprandial glucose levels may have advantages over measuring fasting levels. However, performance of all screening tests is dependent on the cutoff point selected. Unfortunately, there are no well-defined and validated cutoff points to define positive tests. A two-stage screening test strategy may assist with a more efficient use of resources, although such approaches have not been rigorously tested. The optimal interval for screening is unknown. Even though periodic, targeted, and opportunistic screening within the existing health care system seems to offer the greatest yield and likelihood of appropriate follow-up and treatment, much of the reported experience with screening appears to be episodic poorly targeted community screening outside of the existing health care system. Statistical models have helped to answer some of the key questions concerning areas in which there is lack of empirical data. Current models need to be refined with new clinical and epidemiological information, such as the UKPDS results (200). In addition, future models need to include better information on the natural history of the preclinical phase of diabetes. Data from ongoing clinical trials of screening and treatment of impaired glucose tolerance, such as the Diabetes Prevention Program, may eventually offer more direct evidence for early detection and treatment of asymptomatic hyperglycemia (201). It will be important to use comprehensive cardiovascular disease modules that assess the conjoint influence of glucose and cardiovascular risk factor reduction, information on QOL, and refined economic evaluations using common outcome measures (cost per life-year or QALY gained) (11,178,202-204). Such studies should consider all of the costs associated with a comprehensive screening program, including, at a minimum, the direct costs of screening, diagnostic testing, and care for patients with diabetes detected through screening. Finally, combinations of screening tests and different screening intervals should be evaluated within economic studies to allow selection of the optimal approach within the financial and resource limitations of the health care system.

Blood Glucose↗
PubMed2000

Diabetes and physical disability among older U.S. adults.

OBJECTIVE: To estimate the prevalence of physical disability associated with diabetes among U.S. adults > or =60 years of age. RESEARCH DESIGN AND METHODS: We analyzed data from a nationally representative sample of 6,588 community-dwelling men and women > or =60 years of age who participated in the Third National Health and Nutrition Examination Survey. Diabetes and comorbidities (coronary heart disease, intermittent claudication, stroke, arthritis, and visual impairment) were assessed by questionnaire. Physical disability was assessed by self-reported ability to walk one-fourth of a mile, climb 10 steps, and do housework. Walking speed, lower-extremity function, and balance were assessed using physical performance tests. RESULTS: Among subjects > or =60 years of age with diabetes, 32% of women and 15% of men reported an inability to walk one-fourth of a mile, climb stairs, or do housework compared with 14% of women and 8% of men without diabetes. Diabetes was associated with a 2- to 3-fold increased odds of not being able to do each task among both men and women and up to a 3.6-fold increased risk of not being able to do all 3 tasks. Among women, diabetes was also associated with slower walking speed, inferior lower-extremity function, decreased balance, and an increased risk of falling. Of the >5 million U.S. adults > or =60 years of age with diabetes, 1.2 million are unable to do major physical tasks. CONCLUSIONS: Diabetes is associated with a major burden of physical disability in older U.S. adults, and these disabilities are likely to substantially impair their quality of life.

Activities of Daily Living↗
PubMed1999

Diabetes mellitus and serum carotenoids: findings from the Third National Health and Nutrition Examination Survey.

Little is known about carotenoids, a diverse group of plant compounds with antioxidant activity, and their association with diabetes, a condition characterized by oxidative stress. Data from phase I of the Third National Health and Nutrition Examination Survey (1988-1991) were used to examine concentrations of alpha-carotene, beta-carotene, cryptoxanthin, lutein/zeaxanthin, and lycopene in 40- to 74-year-old persons with a normal glucose tolerance (n = 1,010), impaired glucose tolerance (n = 277), newly diagnosed diabetes (n = 148), and previously diagnosed diabetes (n = 230) based on World Health Organization criteria. After adjustment for age, sex, race, education, serum cotinine, serum cholesterol, body mass index, physical activity, alcohol consumption, vitamin use, and carotene and energy intake, geometric means of beta-carotene were 0.363, 0.316, and 0.290 micromol/liter for persons with a normal glucose tolerance, impaired glucose tolerance, and newly diagnosed diabetes, respectively (p = 0.004 for linear trend), and geometric means for serum lycopene were 0.277, 0.259, and 0.231 micromol/liter, respectively (p = 0.044 for linear trend). All serum carotenoids were inversely related to fasting serum insulin after adjustment for confounders (p < 0.05 for each carotenoid). If confirmed, these data suggest new opportunities for research that include exploring a possible role for carotenoids in the pathogenesis of insulin resistance and diabetes.

Adult↗
PubMed1999

Causes of death and associated factors among patients with non-insulin-dependent diabetes mellitus in Taipei, Taiwan.

A cohort of 766 patients with non-insulin-dependent diabetes mellitus (NIDDM) from a general teaching hospital in Taipei, Taiwan were followed prospectively to assess survival experience and associated risk factors. Data were abstracted from the medical records and additional information was obtained from patients or their closest relatives using a structured questionnaire. Date and cause of death were determined from death certificates. Standardized mortality ratios were calculated by the direct method. Chi2-Square test and Cox's proportional hazard analysis were used to control for potential confounders. During a median follow-up of 3.5 years (range 1 month to 4.6 years), 131 deaths occurred. Of these, 29.8% were due to cardiopulmonary disease (ICD 401-429), 13.0% due to cerebrovascular disease (ICD 430-438), 13.0% due to acute diabetes metabolic complications (250.1, 250.2), and 11.4% due to nephropathy (580-589). Adjusted for age, people with NIDDM had 2.2 (95% CI 1.6-2.9) times the risk of death than members of the general population, and cause-specific standardized mortality ratios were: CPD 4.6, nephropathy 8.8, cerebrovascular disease 1.9, and neoplasm 0.7. Age, fasting plasma glucose, hypertension, and proteinuria were positively and independently associated with all-cause mortality (P < 0.05 for each). Thus, NIDDM patients have higher mortality rates than the general population in Taiwan, and age, fasting plasma glucose, hypertension, and proteinuria are associated with this excess risk. Proper application of available interventions may control these factors with a consequent reduction in mortality. Particular attention is needed to prevent deaths from the acute metabolic complications of diabetes.

Adult↗
PubMed1999

High prevalence of impaired fasting glucose and type 2 diabetes mellitus in Penghu Islets, Taiwan: evidence of a rapidly emerging epidemic?

The purpose of this study was to estimate the prevalence of type 2 diabetes and impaired fasting glucose (IFG) in Penghu, Taiwan and compare these estimates with those of the US (NHANES III). Diabetes and IFG (American Diabetes Association criteria, 1997) were assessed among a stratified random sample of 2500 residents of Penghu Islands, Taiwan. The prevalence (age-adjusted to world adult population) of diabetes and IFG were 16.8% (95% CI 15.0-18.6) and 21.0% (95% CI 19.0-23.0), respectively, among Penghu Islanders in Taiwan. Age sex-specific diabetes prevalence ranged from 10.0% in men aged 40-49 years to 29.4% in women aged 60-69 years. Prevalence of IFG ranged from 14.7% in women aged 40-49 years to 30.7% in men aged 50-59 years. Age, body mass index (BMI), and family history of diabetes were each independently associated with both diabetes and IFG. In addition, female gender, apolipoprotein B and triglyceride concentrations were associated with diabetes, and hypertension and apolipoprotein B concentration with IFG. Among persons > or = 40 years in Penghu, Taiwan, the prevalence of diabetes is up to a third higher and the prevalence of IFG is up to three times higher than comparably aged Americans, despite their having a mean BMI 2.2-3.2 kg/m2 lower than Americans. The alarmingly high prevalence of IFG in Taiwan may indicate an emerging diabetes epidemic.

Adult↗
PubMed1999

The use of population attributable risk to estimate the impact of prevention and early detection of type 2 diabetes on population-wide mortality risk in US males.

The Population Attributable Risk (PAR) represents the proportion of the deaths (in a specified time) in the whole population that may be preventable if a cause of mortality were totally eliminated. This population-based measure was used to assess the potential impact of three public health interventions for type 2 diabetes (early detection + standard therapy; early detection + intensive therapy; and primary prevention) on the mortality risk from all causes and from cardiovascular (CVD) diseases. Potential reduction in mortality risks for several levels of compliance or implementation (25%, 50%, 75%, 100%) for each intervention were also estimated. Results suggest that among males aged 45-74 years, the interventions may have greater population-wide impact on total deaths among black males, and greater impact on the CVD deaths among white males. Overall, primary prevention (reduction in all-cause mortality 6.2-10.0%, and CVD mortality 7.9-9.0%) may offer greater marginal benefit than screening and early treatment (reduction in all-cause mortality 3.5-8.3%, and CVD mortality 2.8-8.6%). Often the question facing policy makers is not simply whether to but how much of an intervention is worth implementing? Estimated benefits for various intensities of intervention (as provided) may be useful to assess the likely marginal benefits of each intervention, and can be especially useful if combined with estimated marginal costs.

Black or African American↗
PubMed1999

Impact of diabetes mellitus on mortality associated with pneumonia and influenza among non-Hispanic black and white US adults.

OBJECTIVES: This study assessed the impact of diabetes on mortality associated with pneumonia and influenza among non-Hispanic Black and White US adults. METHODS: Data were derived from the National Mortality Followback Survey (1986) and the National Health Interview Survey (1987-1989). RESULTS: Regardless of race, sex, and socioeconomic status, people with diabetes who died at 25 to 64 years of age were more likely to have pneumonia and influenza recorded on the death certificate than people without diabetes who died at comparable ages (odds ratio [OR] = 4.0, 95% confidence interval [CI] = 2.3, 7.7). For those 65 years and older, the risk remained elevated among Whites with diabetes (OR = 2.2, 95% CI = 1.7, 2.7) but not among Blacks with diabetes (OR = 1.0, 95% CI = 0.6, 1.7). It was estimated that about 17,000 (10.3%) of the 167,000 deaths associated with pneumonia and influenza that occurred in 1986 were attributable to diabetes. CONCLUSIONS: The impact of diabetes on deaths associated with pneumonia and influenza is substantial. Targeted immunizations among people with diabetes may reduce unnecessary deaths associated with pneumonia and influenza.

Adult↗
PubMed1999

The direct health care costs of obesity in the United States.

OBJECTIVES: Recent estimates suggest that obesity accounts for 5.7% of US total direct health care costs, but these estimates have not accounted for the increased death rate among obese people. This article examines whether the estimated direct health care costs attributable to obesity are offset by the increased mortality rate among obese individuals. METHODS: Data on death rates, relative risks of death with obesity, and health care costs at different ages were used to estimate direct health care costs of obesity from 20 to 85 years of age with and without accounting for increased death rates associated with obesity. Sensitivity analyses used different values of relative risk of death, given obesity, and allowed the relative costs due to obesity per unit of time to vary with age. RESULTS: Direct health care costs from 20 to 85 years of age were estimated to be approximately 25% lower when differential mortality was taken into account. Sensitivity analyses suggested that direct health care costs of obesity are unlikely to exceed 4.32% or to be lower than 0.89%. CONCLUSIONS: Increased mortality among obese people should be accounted for in order not to overestimate health care costs.

Adult↗
PubMed1999

Prevalence of self-rated visual impairment among adults with diabetes.

OBJECTIVES: This study estimated the prevalence of self-rated visual impairment among US adults with diabetes and identified correlates of such impairment. METHODS: Self-reported data from the 1995 Behavioral Risk Factor Surveillance System survey of adults 18 years and older with diabetes were analyzed. Correlates of visual impairment were examined by multiple logistic regression analysis. RESULTS: The prevalence of self-rated visual impairment was 24.8% (95% confidence interval [CI] = 22.3%, 27.3%). Among insulin users, multivariable-adjusted odds ratios were 4.9 (95% CI = 2.6, 9.2) for those who had not completed high school and 1.8 (95% CI = 1.0, 2.8) for those who had completed high school compared with those with higher levels of education. Comparable estimates of odds ratios for nonusers of insulin were 2.2 (95% CI = 1.4, 3.4) and 1.3 (95% CI = 0.9, 2.0), respectively. Among nonusers, the adjusted odds for minority adults were 2.4 (95% CI = 1.0, 3.7) times the odds for non-Hispanic Whites. CONCLUSIONS: By these data, 1.6 million US adults with diabetes reported having some degree of visual impairment. Future research on the specific causes of visual impairment may help in estimating the avoidable public health burden.

Adult↗
PubMed1999

HDL cholesterol subfractions and risk of developing type 2 diabetes among Pima Indians.

OBJECTIVE: To examine the relationships between HDL cholesterol subfractions and the incidence of type 2 diabetes and to evaluate potential sex differences in these relationships. RESEARCH DESIGN AND METHODS: Proportional hazards analyses were performed to examine the relationships between HDL subfractions and the development of type 2 diabetes in Pima Indian women and men. Results were controlled for age, BMI, systolic blood pressure, and 2-h glucose. RESULTS: Some 54 of 123 women and 25 of 50 men developed type 2 diabetes during a mean follow-up of 10 (2-19) years. For women, in separate models, high levels of total HDL, HDL2a, and HDL3 were negatively associated with incidence of type 2 diabetes; results were unchanged in models further controlled for fasting insulin level or alcohol consumption. For men, the results were inconsistent and associated with wide confidence intervals; high total HDL and HDL3 were positively associated with incidence of type 2 diabetes in models further controlled for fasting insulin level, but the risk estimates were attenuated in models further controlled for alcohol consumption. CONCLUSIONS: High levels of total HDL, HDL2a, and HDL3 were potential protective factors against type 2 diabetes in women after accounting for alcohol consumption and insulin resistance. High levels of total HDL and HDL3 were predictive of type 2 diabetes in men; the relationship in men appeared to be due to an association with alcohol consumption. The sex differences in the effects of HDL cholesterol may be related to the effects of sex hormones or lipoproteins.

Adult↗