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Biomedical subjects

K M Narayan

Publications and source records attributed to K M Narayan.

At least 55 records · Page 3Linked to original sources
PubMed1998

Randomized clinical trial of lifestyle interventions in Pima Indians: a pilot study.

A pilot trial was conducted to test adherence to specific lifestyle interventions among Pima Indians of Arizona, and to compare them for changes in risk factors for diabetes mellitus. Ninety-five obese, normoglycaemic men and women, aged 25-54 years, were randomized to treatments named 'Pima Action' (Action) and 'Pima Pride' (Pride), which were tested for 12 months. Action involved structured activity and nutrition interventions, and Pride included unstructured activities emphasizing Pima history and culture. Adherence to interventions, changes in self-reported activity and diet, and changes in weight, glucose concentrations, and other risk factors were assessed regularly. Thirty-five eligible subjects who had declined randomization were also followed as an 'observational' group and 22 members of this group were examined once at a median of 25 months for changes in weight and glucose concentration. After 12 months of intervention, members of both intervention groups reported increased levels of physical activity (median: Action 7.3 h month(-1), Pride 6.3 h month(-1), p < 0.001 for each), and Pride members reported decreased starch intake (28 g, p = 0.008). Body mass index, systolic and diastolic blood pressures, weight, 2-h glucose and 2-h insulin had all increased in Action members (p < 0.003 for each), and waist circumference had decreased in Pride members (p = 0.05). Action members gained more weight than Pride members (2.5 kg vs 0.8 kg, p = 0.06), and had a greater increase in 2-h glucose than Pride members (1.33 mM vs 0.03 mM, p = 0.007). Members of the observational group gained an average of 1.9 kg year(-1) in weight and had an increase of 0.36 mM year(-1) in 2-h glucose. Sustaining adherence in behavioural interventions over a long term was challenging. Pimas may find a less direct, less structured, and more participative intervention more acceptable than a direct and highly structured approach.

Adult↗
PubMed1998

Dietary calcium and blood pressure in a Native American population.

OBJECTIVE: To assess the relationship between dietary calcium and blood pressure. METHODS: Cross-sectional study of 404 adult Pima Indians of Arizona. Dietary variables were assessed by the 24-hour recall. Hypertension (HTN) was defined as systolic blood pressure (SBP) > or = mmHg or diastolic blood pressure (DBP) > or = 90 mmHg or drug treatment. RESULTS: Controlled for age and sex, dietary calcium intake was higher in subjects with HTN than in those without (p < 0.01), and higher dietary calcium was associated with a higher prevalence of HTN (odds ratio comparing highest with lowest tertile group of calcium = 2.6, 95% CI 1.4-4.8). Age-sex-adjusted men DBP in low, middle and high tertiles of calcium was 74, 76, and 79 mmHg, respectively (p < 0.001). SBP was not significantly different in the three tertiles (p = 0.07). Multiple regression analyses that controlled for age, sex, body mass index, sodium, potassium and alcohol also suggested a positive association between DBP and dietary calcium (p < 0.01), an association which was stronger at higher glucose concentrations (p < 0.01 for the calcium-glucose interaction). CONCLUSION: In Pima Indians, a population with a high incidence of diabetes, the inverse association between dietary calcium and blood pressure reported in other populations was not found.

Adolescent↗
PubMed1998

Population-based assessment of the level of care among adults with diabetes in the U.S.

OBJECTIVE: To estimate the levels of use of preventive care and to identify correlates of such care among people with diabetes in the U.S. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted using a sample of 2,118 adults, age > or =18 years, with self-reported diabetes in 22 states that participated in the 1994 Behavioral Risk Factor Surveillance System. Most subjects were age > or =45 years (83%), women (51%), and white (75%) and were diagnosed at ages > or =30 years (83%), had type 2 diabetes (89%), and were not using insulin (66%). RESULTS: Among all people with diabetes, 78% practiced self-monitoring of blood glucose, and 25% were aware of the term "glycosylated hemoglobin" or "hemoglobin A one C" (HbA1c). In the last year, 72% of the subjects visited a health care provider for diabetes care at least once, 61% had their feet inspected at least once, and 61% received a dilated eye examination. Controlled for age and sex, the odds ratios (ORs) for insulin use were for self-monitoring (OR [95% CI]; 4.0 [2.6-6.1]); having heard of HbA1c or receipt of a dilated eye examination (1.9 [1.4-2.5]); at least one visit to a provider (3.4 [1.9-7.2]); and feet inspected at least once (2.1 [1.5-2.9]). In addition, people <45 years, those who did not complete high school, and those without insurance coverage were high-risk groups for underuse of preventive care. Only 3% of insulin users and 1% of nonusers met all five of the American Diabetes Association standards in the previous year. CONCLUSIONS: Underuse of recommended preventive care practices is common among people with diabetes.

Adolescent↗
PubMed1998

A project to reduce the burden of diabetes in the African-American Community: Project DIRECT.

Project DIRECT (Diabetes Interventions Reaching and Educating Communities Together) is the first comprehensive community diabetes demonstration project in the United States in an African-American community. This article describes its intervention components and evaluation design. The development and implementation of Project DIRECT has included the community since the project's beginning. Interventions are targeted in three areas: health promotion (improving diet and physical activity levels), outreach (improving diabetes awareness, detection of undiagnosed diabetes, and ensuring that persons with diabetes who are not receiving continuing diabetes care are integrated into the health-care system), and diabetes care (improving self-care, increasing access, and improving the quality of diabetes preventive care received within the health-care system). Evaluation will be internal (conducted by Project DIRECT staff to assess process outcomes in persons directly exposed to each specific intervention) and external (review of outcomes to assess the impact of the multi-intervention program at the level of the entire community). Because diabetes exacts a disproportionate toll among African Americans, the findings from this project should aid in developing strategies to lessen the burden of this disorder, particularly among minority populations.

Black or African American↗
PubMed1997

Serum cholesterol and mortality rates in a Native American population with low cholesterol concentrations: a U-shaped association.

BACKGROUND: Low serum cholesterol concentrations are associated with high death rates from cancer, trauma, and infectious diseases, but the meaning of these associations remains controversial. The present report evaluates whether low cholesterol is likely to be a causal factor for mortality from all causes or from specific causes. METHODS AND RESULTS: Among 4553 Pima Indians > or =20 years old, a population with low serum cholesterol (median, 4.50 mmol/L), 1077 deaths occurred during a mean follow-up of 12.8 years. Trauma was the most common cause. The relationship between serum cholesterol measured at 2-year intervals and age- and sex-standardized mortality rates was U-shaped. Cholesterol was related positively to mortality from cardiovascular diseases and diabetes (including nephropathy) and negatively to mortality from cancer and alcohol-related diseases. The relationship was U-shaped for mortality from infectious diseases, and cholesterol was not related to mortality from trauma. Change in cholesterol from one examination to the next was positively related to mortality from diabetes. In proportional-hazards models adjusted for potential confounders, the relationship between baseline cholesterol and mortality was U-shaped for all causes and diabetes and positive for cardiovascular diseases. Other relationships were nonsignificant. Among 3358 subjects followed > or =5 years, the relationship was significant and positive only for mortality from cardiovascular diseases. CONCLUSIONS: Despite a high exposure risk for Pima Indians, if low cholesterol level is a causal factor, the relationships between low serum cholesterol and high mortality rates probably result from diseases lowering cholesterol rather than from a low cholesterol causing the diseases.

Adult↗
PubMed1997

Plasma lipoproteins and incidence of non-insulin-dependent diabetes mellitus in Pima Indians: protective effect of HDL cholesterol in women.

The role of plasma lipoproteins in the development of non-insulin-dependent diabetes mellitus (NIDDM) was studied in 787 non-diabetic (2-h glucose < 11.1 mmol/l) Pima Indians (265 men and 522 women). Subjects were followed for a mean of 9.8 (range: 1.8-16.4) years, during which 261 (76 men and 185 women) developed NIDDM. In men and women, very-low-density lipoprotein (VLDL) cholesterol, VLDL triglyceride, low-density lipoprotein triglyceride and total triglyceride, controlled for age, predicted NIDDM (P < 0.01 for each). These effects diminished when controlled for age, sex, body mass index, systolic blood pressure and 2-h glucose. However, high-density lipoprotein (HDL) cholesterol, controlled for age, body mass index, systolic blood pressure and 2-h glucose, was a significant protective factor for NIDDM in women (hazard rate ratio (HRR) = 0.35, 95% CI (0.23-0.54), P < 0.001, 90th compared with 10th percentile) but not in men (HRR = 1.04, 95% CI (0.53-2.05), P = 0.915). This association remained significant in women when controlled for fasting or 2-h plasma insulin concentrations, other estimates of insulin resistance or alcohol consumption. The protective effect of HDL cholesterol was similar among women with normal (2-h glucose < 7.8 mmol/1) or impaired (7.8 mmol/l < or = 2-h glucose < 11.1 mmol/l) glucose tolerance at baseline. These results indicate that lipoprotein disorders are an early accompaniment of the abnormalities that lead to NIDDM.

Adult↗
PubMed1997

Seat restraint use, previous driving history, and non-fatal injury: quantifying the risks.

AIMS: To quantify the increased risk of non-fatal injury when children travel unrestrained in a car, and to identify other preventable risk factors. METHODS: Case-control study of 78 children presenting to an accident and emergency (A&E) department having sustained an injury while travelling in a car, and 97 children attending an A&E outpatient clinic with conditions unrelated to road traffic accidents. RESULTS: Seat restraint was associated with a 93% lower risk of child accident injury. A driver with points on the licence was over five times more likely to have had an accident resulting in child injury than a driver without points. Child accident injury was also associated with the driver's accident history. CONCLUSIONS: These data allow the effect of achieving new target levels of seat restraint use to be estimated. Strategies aimed at reducing the risk of further accident among drivers with a history of accident may have a beneficial impact on childhood accident injuries.

Accidents, Traffic↗
PubMed1996

Prevalence and patterns of smoking in Delhi: cross sectional study.

OBJECTIVE: To determine the prevalence and predictors of smoking in urban India. DESIGN: Cross sectional. SETTING: Delhi, urban India, 1985-6. SUBJECTS: Random sample of 13,558 men and women aged 25-64 years. MAIN OUTCOME MEASURES: Smoking prevalence; subjects who were currently smoking and who had smoked > or = 100 cigarettes or beedis or chuttas in their lifetime were defined as smokers. RESULTS: 45% (95% confidence interval 43.8 to 46.2) of men and 7% (6.4 to 7.6) of women were smokers. Education was the strongest predictor of smoking, and men with no education were 1.8 (1.5 to 2.0) times more likely to be smokers than those with college education, and women with no education were 3.7 (2.9 to 4.8) times more likely. Among smokers, 52.6% of men and 4.9% of women smoked only cigarettes while the others also smoked beedi or chutta. Compared with cigarette smokers, people smoking beedi or chutta were more likely to be older and married; have lower education, manual occupations, incomes, and body mass index; and not drink alcohol or take part in leisure exercise. CONCLUSION: There are two subpopulations of smokers in urban India, and the prevention strategy required for each may be different. The educated, white collar cigarette smoker in India might respond to measures that make non-smoking fashionable, while the less educated, low income people who smoke beedi or chutta may need strategies aimed at socioeconomic improvement.

Adult↗
PubMed1996

Incidence of diabetes mellitus in women following impaired glucose tolerance in pregnancy is lower than following impaired glucose tolerance in the non-pregnant state.

Impaired glucose tolerance (IGT), which is asymptomatic and requires a glucose tolerance test for detection, is a well-known risk factor for diabetes mellitus. Outside the research setting it is rarely identified in people who lack specific risk factors for diabetes except during pregnancy, at which time screening with an oral glucose challenge is a routine procedure. A 75-g oral glucose tolerance test was performed during the latter part of pregnancy or during a routine epidemiology survey in 15-39-year-old Pima Indian women with no history of abnormal glucose tolerance. Those with IGT by World Health Organization criteria were included in this study. Diabetes incidence in women was compared between those whose IGT was first detected during pregnancy and those who were not pregnant when IGT was first recognized. Seventeen of 73 pregnant women and 114 of 244 non-pregnant women developed diabetes within 10 years. When controlled for plasma glucose concentration, age, body mass index, parity and duration of follow-up, those who were not pregnant were at higher risk of developing diabetes than those who were pregnant (hazard rate ratio = 1.71, 95% confidence interval = 1.01-2.91). Previous studies had reported that women with IGT during pregnancy are at higher risk of diabetes than women with normal glucose tolerance. This study suggests that women with IGT during pregnancy are at lower risk than non-pregnant women with a similar plasma glucose concentration who, in the clinical setting, are likely to remain unrecognized.

Adolescent↗
PubMed1996

Relationship of locus of control to physical activity among people with and without diabetes.

OBJECTIVE: To examine the relationship between locus of control (LOC) (internal and external) and physical activity in Pima Indians and to determine whether this relationship is affected by the presence of diabetes. RESEARCH DESIGN AND METHODS: A population-based sample of 580 Pima Indians was recruited from an ongoing research study. LOC was measured on a 1-40 modified Rotter scale, and past year total physical activity (leisure and work physical activity levels combined) was measured by interviewer-administered questionnaire. RESULTS: Among both men and women without diabetes, individuals with an internal LOC (score 1-16) were significantly (P < 0.01) more active than those with an external (score 17-40) LOC (70 vs. 30 median metabolic equivalent [MET] hours per week for men: 12 vs. 5 median MET hours per week for women). Controlled for age and BMI, an internal LOC was significantly associated with a higher level of physical activity among men (P = 0.04) and women (P = 0.001) without diabetes, but not among those with diabetes. CONCLUSIONS: Nondiabetic Pima Indians with an internal LOC are more physically active than those with an external LOC. Enhancing perceptions of internal control may influence physical activity and thus have implications for diabetes prevention.

Adolescent↗
PubMed1996

Familial aggregation of medial arterial calcification in Pima Indians with and without diabetes.

OBJECTIVE: Little is known about medial arterial calcification (MAC) other than its association with age, sex, diabetes, and diabetes complications. Familial aggregation of this disorder was studied to determine the importance of potential genetic factors and to assess whether such familial aggregation was independent of that of diabetes. RESEARCH DESIGN AND METHODS: Members of 1,256 Pima Indian nuclear families with 3,339 offspring were examined radiologically for MAC of the feet. Multiple logistic regression analyses were used to compare the presence of the disorder in a parent with the presence of MAC in an offspring and to determine whether familial aggregation of MAC was independent of parental diabetes. RESULTS: Controlled for age, sex, diabetes, serum cholesterol, and blood pressure, offspring of one parent with MAC had 3.3 (95% CI 1.5-7.6) times the odds of MAC as did offspring of parents without MAC, and offspring with both parents affected had an even higher risk (odds ratio, 8.1; 95% CI 3.4-18.8). Controlled for offspring age and sex and for parental age and diabetes, parental MAC was associated with the disorder in offspring (P < 0.001), but the effect of parental diabetes on MAC in the offspring was not significant when controlled for parental MAC (P = 0.36). Furthermore, offspring of nondiabetic parents with MAC, controlled for age, sex, diabetes, and diabetes duration, had 1.7 (95% CI 0.9-3.1) times the odds of MAC than did offspring of diabetic parents with MAC. CONCLUSIONS: Independent of parental age and diabetes and offspring age, sex, diabetes, and diabetes complications, parental MAC confers an increased risk of MAC in offspring. These findings suggest that the factors responsible for the familial clustering of MAC may be different from those for diabetes.

Adult↗
PubMed1996

A two-step strategy for identification of high-risk subjects for a clinical trial of prevention of NIDDM.

OBJECTIVE: To evaluate 2-h plasma glucose (2HPG), fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1), a combination of FPG and HbA1 (FPG-HbA1), and other factors as screening tests for identifying high-risk subjects for a clinical trial of prevention of NIDDM and to identify strategies to minimize the total number of oral glucose tolerance tests (OGTTs) required to recruit eligible subjects to the trial. RESEARCH DESIGN AND METHODS: One thousand, one hundred and eight nondiabetic Pima Indians aged 25-64 years were followed for up to 5 years, and factors predicting NIDDM, defined by World Health Organization criteria (2HPG > or = 11.1 mmol/l), were assessed using Cox's proportional hazards analysis. Various threshold values of FPG, HbA1, and FPG-HbA1 were determined, which, when combined with an OGTT, identified subjects with impaired glucose tolerance (IGT) (2HPG > or = 7.8 and < 11.1 mmol/l) at a number of specified risks for developing NIDDM in 5 years. The value of each of the three tests was then assessed by calculating (for each threshold) the numbers to be screened, the numbers requiring an OGTT, and the sample size of IGT subjects needed to detect a 33% reduction in NIDDM by an experimental intervention at a power of 80%. RESULTS: During a median of 4.3 years of follow-up, 91 (8.2%) of the 1.108 nondiabetic subjects developed NIDDM. The estimated 5-year cumulative incidence rate was 13.5%. Each of the variables, 2HPG, FPG, HbA1, FPG-HbA1, BMI, IGT, and systolic (sBP), diastolic (dBP), and mean (MBP) blood pressures, predicted NIDDM (P < 0.05 for each) when controlled for age and sex. In a stepwise proportional hazards analysis model, 2HPG and FPG-HbA1 (P < 0.001 for each) were selected as the best set of predictors of NIDDM and of fasting hyperglycemia (FPG > or = 7.8 mmol/l). CONCLUSIONS: A two-step strategy, in which high-risk individuals are first identified by FPG or FPG-HbA1 and then the OGTT is used to select subjects with IGT, requires fewer OGTTs than when using 2HPG as the initial screening test without substantially increasing the numbers that would need to be screened. Such a strategy also offers the advantage of reducing the necessary sample size and is therefore an effective, efficient, and convenient method of identifying eligible subjects for a clinical trial of prevention of NIDDM.

Adult↗
PubMed1996

Weight fluctuation, mortality and vascular disease in Pima Indians.

OBJECTIVE: To examine the relationship of weight fluctuation to mortality rates and incidence of vascular disease. SUBJECTS: A cohort of Pima Indians, 572 of whom had non-insulin-dependent diabetes mellitus and 766 without diabetes. DESIGN: Individuals were invited biennially to research examinations. The root mean square error (RMSE) of the linear trend of weight with time for the first four examinations after age 20 years was used as an index of weight fluctuation. Subjects were followed from the fourth examination until death or until 31 December 1991. The mortality rate ratio (MRR) and its 95% confidence interval (CI) for those with a high weight fluctuation index relative to those with a lower value were determined. The median duration of follow up was 9.3 (range 0.1-22.6) years. MEASUREMENTS: All cause mortality (n = 356); incidence of diabetic retinopathy (n = 145), diabetic nephropathy (n = 132) and electrocardiographic abnormalities (n = 82). RESULTS: There was no significant relationship between weight fluctuation and mortality for diabetic subjects (MRR = 1.0, 95% CI 0.8-1.3, p = 0.91). Nondiabetic subjects with a high weight fluctuation index had a higher mortality rate than those with a lower index (MRR = 1.5, 95% CI 1.0-2.1, p = 0.03); the association was stronger among men than among women. The excess mortality in the high weight fluctuation group was not due to cardiovascular diseases, but to noncardiovascular causes and the risk for alcohol-related death was particularly increased. Weight fluctuation was not associated with the incidence of diabetic retinopathy, nephropathy or electrocardiographic abnormalities. CONCLUSIONS: A high weight fluctuation index was associated with higher mortality rates in nondiabetic, but not in diabetic, Pima Indians. The excess mortality is largely due to noncardiovascular causes of death and may reflect lifestyle factors associated with weight fluctuation, rather than its metabolic effects.

Adult↗