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V Collins

Publications and source records attributed to V Collins.

17 recordsLinked to original sources
PubMed1997

Hyperleptinaemia: the missing link in the, metabolic syndrome?

Leptin's association with fasting insulin raises the possibility that hyperleptinaemia is an additional component of the Metabolic Syndrome, or perhaps underlies the syndrome. This population-based study of Western Samoans examined the relationship of serum leptin with insulin sensitivity assessed by Homeostatic Model Assessment (HOMA) and components of the Metabolic Syndrome. Two hundred and forty subjects (114 men, 126 women), aged 28-74 years, were drawn from a study conducted in 1991. An oral glucose tolerance test indicated that 59 subjects had diabetes. Diabetic men had higher leptin levels than non-diabetic (6.0 vs 3.2 ng ml-1) but this difference was no longer significant after adjustment for BMI. Leptin levels in diabetic women (24.7 ng ml-1) non-diabetic women (22.6 ng ml-1) were not different. Leptin was strongly, positively correlated with BMI, fasting insulin and mean blood pressure after adjusting for age and sex (r > 0.43, p < 0.001), irrespective of glucose tolerance status. Linear regression models indicated that leptin was associated with insulin sensitivity independent of age, BMI, waist/hip ratio, triglycerides, HDL-cholesterol, and hypertension. Similar models were computed with mean blood pressure or triglycerides as the dependent variable, and including insulin sensitivity with the independent variables. Leptin was independently associated with mean blood pressure in men, but was not independently associated with triglycerides. Mean levels of 2-h insulin, triglycerides, LDL-cholesterol, and systolic blood pressure varied across tertiles of leptin in men after adjusting for age, BMI, and insulin sensitivity, and mean levels in the top tertile tended to be higher than in the lowest tertile. These results indicate an independent relationship between leptin and insulin sensitivity, but the equivocal results concerning associations of leptin with components of the Metabolic Syndrome make it unlikely that leptin affects these directly.

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PubMed1997

Risk factors for coronary heart disease in a population with a high prevalence of obesity and diabetes: a case-control study of the Polynesian population of Western Samoa.

OBJECTIVE: To evaluate anthropometric, haemodynamic and biochemical risk markers for coronary heart disease (CHD) in the Polynesian population of Western Samoa in a case-control study of 43 cases of CHD compared with 90 age- (mean 53 years) and sex-matched controls. METHODS: Cases were identified on the basis of a 12-lead electrocardiogram and clinical history. RESULTS: More than 60% of the participants had a body mass index > or =30 kg/m2 and nearly 80% had central obesity. Both diabetes mellitus (17%) and impaired glucose tolerance (9%) were also common in this population. Nineteen per cent of the population were hypertensive and both antihypertensive therapy (21 versus 1%, P<0.001, risk 23.6) and hypertension (35 versus 11%, P<0.01, risk 4.3) were significantly more common among cases than they were among controls. In addition, the plasma high-density lipoprotein cholesterol level was lower (1.00+/-0.09 versus 1.24+/-0.05 mmol/l, P<0.05) and the plasma urate level was higher (0.42+/-0.02 versus 0.37+/-0.01 mmol/l, P<0.05) in the female cases than they were in their respective controls. Low-density lipoprotein (LDL) particle sizing did not reveal an excess of small LDL particles to be a feature of CHD cases, but more than 70% both of cases and of controls had multiple LDL species. The response of the triglyceride level to a fat-rich meal was the same for CHD cases and controls. CONCLUSION: The population studied had a high prevalence of several risk factors for CHD, including obesity and non-insulin-dependent diabetes mellitus; however, the most prominent factor relating to CHD within the community was the presence of hypertension.

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PubMed1994

Blood pressure, hypertension and other cardiovascular risk factors in six communities in Papua New Guinea, 1985-1986.

Surveys of noncommunicable diseases were performed in six communities in Papua New Guinea during 1985-1986. Results are reported here with respect to blood pressure and associated factors in adults. Mean systolic and diastolic blood pressures were lowest, and hypertension was rarest (less than 2%), in three rural/semirural villages on Karkar Island, Madang Province. Intermediate values for blood pressure and moderate prevalence of hypertension (3-6%) were observed in rural and urban Tolai communities in East New Britain Province. A periurban village in the Eastern Highlands Province displayed the highest mean blood pressures and prevalence of hypertension (12% in men and 5% in women). There was a modest rise in mean systolic blood pressure with age in most groups, but the age-related rise in diastolic pressure was much less pronounced. Other cardiovascular risk factors--body mass index (BMI), and plasma cholesterol, glucose and insulin concentrations--were lowest in the least developed rural villages on Karkar Island and highest in the urban Tolai and periurban highland communities. Both systolic and diastolic blood pressures were significantly (and positively) related to age, male sex, BMI and speaking a non-Austronesian language. It is concluded that there is now a considerable variation in the prevalence of hypertension, and the levels of blood pressure and other cardiovascular risk factors, in different communities in Papua New Guinea.

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PubMed1989

Performance of 'Micro-Bumintest' tablets for detection of microalbuminuria in Nauruans.

Subclinical elevation of urinary albumin excretion (microalbuminuria) is useful for the detection of individuals at high risk of developing nephropathy in both insulin-dependent and non-insulin-dependent diabetes mellitus. We have evaluated the performance of Micro-Bumintest, a semi-quantitative test for the rapid detection of microalbuminuria. A total of 1186 samples from a population-based survey of the high diabetes prevalence community of Nauru were studied. Compared with a radioimmunoassay method, the Micro-Bumintest had a sensitivity of 97.6%, specificity of 93.2% and overall efficiency of 94.8%, when 40 micrograms/ml was used as the discriminating albumin concentration defining microalbuminuria. Significant differences in radioimmunoassay results between categories of the Micro-Bumintest were found, indicating its usefulness as a semi-quantitative test. Compared with subjects with normal glucose tolerance, there was a statistically significant progressive increase in the prevalence of microalbuminuria as detected by Micro-Bumintest in subjects with impaired glucose tolerance and diabetes mellitus. Micro-Bumintest performs well as a screening test for detection of microalbuminuria not only in the clinical situation, but also in population-based epidemiological studies.

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PubMed1985

Group comparisons of blood pressure and indices of obesity and salt intake in Pacific populations.

Group comparisons of blood pressure and indices of obesity and salt intake from epidemiological studies conducted in the Pacific early in the 1980s are presented. The comparisons were of a rural-urban type, and showed a trend for a lower prevalence of hypertension and for lower mean blood pressures in adults from rural areas, compared with urban populations. Rural residents were also slimmer and appeared to have a lower salt intake than did urban dwellers. These findings give possible support to the role of adiposity and salt intake in the genesis of essential hypertension.

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PubMed1984

Impaired glucose tolerance in Kiribati.

Subjects with impaired glucose tolerance have been shown to have a higher risk for subsequent diabetes and increased susceptibility to atherosclerosis. Data obtained from a cross-sectional medical survey in Kiribati in 1981 have been studied for evidence as to whether impaired glucose tolerance is a truly separate category of glucose intolerance. Subjects in the impaired glucose tolerance category were compared to both normal and diabetic subjects with respect to the mean values of certain variables including plasma glucose, body mass index, plasma cholesterol, plasma triglycerides, and systolic blood pressure. Differences between impaired glucose tolerant and normal subjects, and between impaired glucose tolerant and diabetic subjects were assessed. The most important differences between groups occurred with respect to plasma glucose concentration, body mass index, and plasma lipids. The results of this study provide further support for the validity of the impaired glucose tolerance category.

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PubMed1984

Ethnic differences in susceptibility to non-insulin-dependent diabetes. A comparative study of two urbanized Micronesian populations.

Two urbanized Micronesian populations were recently studied by population-based diabetes surveys. These were Nauruans living on the island of Nauru, and Gilbertese resident on the islet of Betio, in the Republic of Kiribati (1982 and 1981, respectively). Nauruans are known to suffer from a very high prevalence of non-insulin-dependent (type II) diabetes mellitus (NIDDM). In the present study, the effects of suspected environmental risk factors for diabetes were controlled for, in an attempt to elucidate any residual difference in the prevalence of diabetes between the two groups, which might be of genetic origin. As almost all Nauruans lead a physically inactive lifestyle, only inactive subjects in either population were selected for study. The total study sample consisted of 2306 subjects. After further controlling for the effects of age and obesity, the odds of diabetes for Nauruans, as compared with Gilbertese, were threefold. The multiple logistic regression model showed ethnicity (i.e., being Nauruan) to be the strongest of the predictor variables examined in both sexes. In a random subsample of approximately one-third of the total subjects (N = 694), stratified with respect to age and sex, daily intake of total energy and of three dietary components was assessed. The dietary variables were carbohydrate, fat, and dietary fiber. Fat intake was found to be a weak, but significant predictor of diabetes in females after controlling for age, although dietary fat was not predictive of diabetes after also controlling for ethnicity, or for body mass. None of the other dietary variables had any predictive power in either sex.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1984

Glucose tolerance in a highland population in Papua New Guinea.

A diabetes survey was conducted in the highlands of Papua New Guinea in June 1983. Two villages in the Asaro Valley, Eastern Highlands Province, were selected for study. The subjects were of Melanesian ancestry, and were free of Austronesian genetic admixture. The response rate was 95% and 308 subjects were examined. As defined by current WHO criteria, there was a total absence of non-insulin-dependent diabetes (NIDDM) in these communities. The prevalence of impaired glucose tolerance (IGT) was 2%. These estimates of glucose intolerance are the lowest yet to be reported from the Pacific, using currently accepted diagnostic criteria and standardized survey methods. The 2-hr plasma glucose and insulin concentrations were positively correlated in both sexes. Of the two villages studied, one had undergone a greater degree of acculturation than the other. Both the total distribution and the mean value of 2-hr plasma glucose concentration were lower in the more traditional village, and these findings could not be explained by differences in age or obesity between the two communities. Mean 2-hr plasma insulin concentration did not differ significantly between the two villages, and was very low in both. The results of this study support the theory that Melanesians free of Austronesian genetic admixture are relatively, though not absolutely resistant to the deleterious influence of acculturation upon glucose tolerance seen in other Pacific populations. However, the notion that in this population cultural change has been insufficient, or of too recent onset for a deterioration in glucose tolerance to be manifest cannot be excluded.

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PubMed1983

Plasma glucose distributions in two pacific populations: the bimodality phenomenon.

The frequency distribution of plasma glucose concentrations in certain populations show two distinct sub-groups, viz. the non-diabetic group and a hyperglycaemic group. The two groups show up as a double peak (bimodality) in the best-fit frequency distributions of log plasma glucose, and the separation or cut-off point where the two curves intersect, gives an indication of the plasma glucose level at which diabetes could be diagnosed. Venous plasma glucose concentrations two hours after a 75 gm oral glucose load were determined in the Micronesian population of Nauru and the urban Polynesian population of Western Samoa, in subjects aged 20 years and over. Both communities exhibit bimodal frequency distributions of plasma glucose in the upper age groups in both sexes. In the younger age groups the frequency distribution of plasma glucose typically follows the usual unimodal Gaussian curve. However, the high prevalence Nauruans show the bimodal form in all groups except the youngest males. The data show that among these two communities, as with the Pimas, the frequency distribution of plasma glucose concentrations can be used to separate the population into normal and hyperglycaemic groups.

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