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T K Young

Publications and source records attributed to T K Young.

At least 55 records · Page 3Linked to original sources

Sociocultural and behavioural determinants of obesity among Inuit in the central Canadian Arctic.

This paper reports on the sociocultural determinants of obesity among the Inuit people in the central Canadian Arctic, part of the Keewatin Health Assessment Study (KHAS), a comprehensive community health survey conducted during 1990/91 in eight Inuit communities in the Northwest Territories (n = 434 adults aged 18 yr +). On multivariate analysis, age is an independent predictor of obesity in both sexes. Among Inuit women, non-smoking status and a lower education is associated with various obesity indices. However, smoking is not a predictor in men, and the association with education is the reverse, i.e. the more highly educated are more likely to be obese. In addition, some obesity indices are associated with higher income, an admixed ethnic background, fluency in the Inuit language and less time spent on the land. In general Inuit men tend to show the pattern observed in developing societies, where obesity is more prevalent among those with higher SES status, whereas Inuit women are more characteristic of developed societies, where obesity is associated with a lower SES. The different sex roles in a rapidly modernizing population is most likely to be responsible for this phenomenon.

Adolescent↗

Effect of parathyroid hormone on antioxidant enzyme activity and lipid peroxidation of erythrocytes in five-sixths nephrectomized rats.

The purpose of the study was to investigate the effects of parathyroid hormone (PTH) infusion on antioxidant enzyme activity and lipid peroxidation of erythrocytes in five-sixths nephrectomized (Nx) rats. Five-sixths Nx rats had a higher osmotic fragility in red blood cells (RBC). Thyroparathyroidectomy (TPTX) effectively decreased the abnormality of osmotic fragility in RBC in Nx rats. PTH infusion in Nx-TPTX rats markedly increased the osmotic fragility in RBC. Total glutathione was measured by using the enzyme-recycling method. We found elevated glutathione levels in RBC of five-sixths Nx rats, but this elevation could be inhibited by TPTX and recovered by PTH infusion in Nx-TPTX rats. Five-sixths Nx rats had a lower glutathione peroxidase activity in RBC, but TPTX or PTH infusion was not found to alter the decrease of the glutathione peroxidase activity in RBC of five-sixths Nx rats. These rats had a higher activity in RBC superoxide dismutase as compared with sham-operated controls (p < 0.05), but the higher activity in RBC superoxide dismutase in Nx rats had been inhibited by TPTX. PTH infusion recovered the higher activity in RBC superoxide dismutase in five-sixths Nx-TPTX rats. Nx rats were not found to alter the activity of catalase in RBC. Neither could TPTX or PTH infusion in Nx rats influence the activity of catalase in RBC. A high lipid peroxidation in RBC was found in five-sixths Nx rats, namely, increased formation of malondialdehyde (MDA) in RBC had been induced to produce lipid peroxidation by H2O2, but neither TPTX nor PTH infusion could inhibit or enhance the increase of lipid peroxidation in RBC of Nx rats. These results indicate that PTH infusion did not increase the susceptibility to lipid peroxidation in RBC of five-sixths Nx rats. Thus, the increased osmotic fragility in RBC induced by PTH infusion may not result from the reduction in the RBC defense mechanism against free radical toxicity.

Animals↗

The impact of housing on health: an ecologic study from the Canadian Arctic.

OBJECTIVES AND METHOD: An ecologic study was conducted to investigate the association between housing and health in 49 predominantly Native communities in the Northwest Territories (NWT) in the Canadian Arctic, making use of data from a housing survey and data relating to physical and social health routinely reported to various service delivery agencies. RESULTS: The rate of health centre visits, as a measure of morbidity, correlated with most housing and socioeconomic status (SES) indicators. Communities with worse housing and SES were found to have a higher rate of health centre visits. Using factor analysis, composite housing and SES indicators were constructed. Housing was poorly correlated with any of the outcome variables, whereas SES was strongly correlated with health centre visits and moderately correlated with the occurrence of fires. Communities with worse SES were more likely to have a higher rate of health centre visits but the opposite effect was observed with fires. When both housing and SES indices were included in a multiple regression model, SES was the stronger factor in predicting the rate of health centre visits and fires. No significant association exists between these variables and the frequency of sentenced admissions. CONCLUSIONS: It is possible that improvement in housing quality in the NWT may have eliminated much disparity and perhaps removed most obvious illness-generating housing features. Improved housing through subsidies, however, does not alter other components of SES such as education, employment and income. The importance of SES in health and social well-being is well known and is demonstrated in the NWT as well. This study also shows that ecologic analyses can provide relatively quick and useful data for public health policy.

Analysis of Variance↗

Obesity, central fat patterning, and their metabolic correlates among the inuit of the central Canadian Arctic.

I report on the occurrence and metabolic correlates of obesity among the Inuit (Eskimos) of the central Canadian Arctic using data from the Keewatin Health Assessment Study conducted during 1990 and 1991 in eight Inuit communities in the Northwest Territories (n = 434, adults aged 18 years and older). Data from the 1990 Manitoba Heart Health Survey among 2200 predominantly white residents of the province of Manitoba were used for comparison. Judging by body mass index and two skinfold thicknesses, obesity among the Inuit is as prevalent as it is in the general North American population. This is a new development over the past two or three decades, the result of rapidly changing physical activity, diet, and lifestyle. Obesity is more prevalent among women, among whom there is also a higher degree of central fat patterning based on the waist-to-hip ratio. When different categories of obesity are compared, blood pressure and one or more of the lipids show an increasing trend but glucose or insulin level shows no significant change. This observation distinguishes the Inuit from other populations. Even where a relationship exists, as with triglyceride and HDL cholesterol levels, the magnitude of the response is lower among the Inuit. The differential effect of obesity on glucose, blood pressure, and lipid levels in the Inuit compared with non-Inuit suggests a type of selective insulin resistance, the underlying mechanism of obesity and several chronic diseases. Inuit metabolism reflects their almost exclusive diet of fat and proteins traditionally. From the public health perspective it is important to monitor and ameliorate the impact of changing diet and physical activity on the prevalence of obesity and associated health effects.

Adolescent↗

Decreased tubular reabsorption of zinc in rats with chronic uremia.

Effect of chronic uremia on tubular reabsorption of zinc was studied in rats with different zinc nutritional status. Using inulin clearance to represent glomerular filtration rate and plasma ultrafiltrate to imitate glomerular filtrate in vivo, the glomerular filtered load of zinc was estimated in each rat. The amount of tubular reabsorption of zinc equals the amount of zinc filtered minus the amount of zinc excreted into the urine. Proportion of filtered zinc excreted was estimated to be 2.8-8.7% in control rats and 17.3-29.8% in uremic rats induced by five-sixths nephrectomy. Similarly, proportion of filtered zinc reabsorption decreased significantly from 91.3-97.3% in control rats to 70.1-82.7% in uremic rats. Zinc deficiency increased fractional reabsorption of zinc in uremic rats but not in control rats. Fractional excretion of zinc correlated with both urine flow rate and urinary excretion of protein. The results suggest that uremia toxins may influence tubular reabsorption of zinc even in the presence of renal adaptation to zinc deficiency.

Animals↗

Is noncentral obesity metabolically benign? Implications for prevention from a population survey.

OBJECTIVE: To determine if individuals who are overall obese but have low waist-to-hip ratios have unfavorable lipid profiles, blood pressures, and glucose statuses. DESIGN: Cross-sectional study. SETTING: The Manitoba Heart Health Survey surveyed a representative sample of residents of the Canadian province of Manitoba. PARTICIPANTS: --A total of 2,792 adults aged 18 to 74 years were interviewed, 2,339 of whom underwent clinical examinations. MAIN OUTCOME MEASURES: Blood pressure, fasting plasma glucose, total cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein measurements were compared across categories of body mass index (BMI) and waist-to-hip ratio (WHR). MAIN RESULTS: Manitobans with noncentral obesity tend to occupy positions between those of the nonobese and the centrally obese in terms of the effect on blood pressure, plasma lipids, and glucose. In multiple linear regression models involving age, BMI, and WHR as independent variables and one of the metabolic variables as dependent variables, both BMI and WHR are significant independent predictors of most metabolic variables. Where both are significant, BMI tends to be the stronger predictor, with a larger standardized regression coefficient. CONCLUSIONS: Noncentral obesity is not metabolically benign; BMI as an overall measure of obesity is as important as, and sometimes more important than, WHR in predicting metabolic effects. The recognition of the epidemiological significance of the WHR as a centrality measure of obesity should not divert attention from the metabolic risk status of noncentrally obese individuals who require continued health education to reduce weight.

Adult↗

Alterations with age of the T3-stimulated release of atrial natriuretic peptide and its effect on water and sodium metabolism in rats.

The influence of age on urinary excretion of sodium and water and in vitro release of atrial natriuretic peptide (ANP) were studied in rats. Older rats had increased daily water intake and urine output. They also had increased plasma ANP, decreased right atrial contents of ANP and increased ANP release in response to 10 nM T3. The ageing process may have altered the regulatory mechanisms of water metabolism and secretion of ANP.

Aging↗

Gastric inhibitory polypeptide and gastric acid secretion in pregnant rats.

The effects of pregnancy on the basal and pentagastrin-stimulated gastric acid secretion and the level of plasma gastric inhibitory polypeptide (GIP) in rats were studied on pentobarbital-anaesthetized non-pregnant rats and rats in the 1st, 2nd, or 3rd week of gestation. Acid output was determined by titration of the gastric perfusate. Basal secretion was collected for 45 min before a 30 min infusion of pentagastrin (8 micrograms/ml/300 g body weight). Concentration of plasma GIP was measured by a radioimmunoassay (RIA). The immunoreactivity of GIP-like substance in the extract of the rat placenta collected from the rat at day 21 of gestation was examined by RIA. The biological activity of GIP-like substance in the rat placenta extract was tested by the reduction of pentagastrin-stimulated gastric acid secretion in male rats. The basal level of gastric secretion was higher in late pregnancy as compared with the non-pregnant rats. Pentagastrin induced a greater increase of gastric acid secretion in early but not late pregnant rats as compared with the non-pregnant animals. The basal and post-pentagastrin level of plasma GIP was higher in rats in late pregnancy. Both immunoreactivity and biological activity of GIP exist in the rat placenta extract. These results suggest that the normalization of gastric acid secretion in late pregnant rats is at least in part due to the production of GIP-like substance from placenta.

Animals↗

The population survey as a tool for assessing family health in the Keewatin region, NWT, Canada.

The population survey is an important tool in community health assessment, including the physical and psychological aspects of family health. It provides data on health status and health determinants not available from vital statistics and health service utilization. The Keewatin Health Assessment Study (KHAS), which was designed in collaboration with the Keewatin Regional Health Board (KRHB), surveyed a representative sample of the predominantly Inuit population in 8 communities in the central Canadian Arctic. The entire survey included 874 individuals in all age groups, of whom 440 were children and adolescents under 18 years of age, and consisted of questionnaires, clinical examination and laboratory tests. Of the large number of variables on which data were collected, some were of particular relevance to the health of children and the well-being of the family, including: (1) Child growth and development; (2) Nutrition and diet; (3) Social pathologies: suicide attempts and sexual abuse; (4) Oral health; and (5) Audiologic health. In addition to providing cross-sectional data, survey participants constitute a cohort which, if followed up longitudinally, can be used to determine the incidence of specific conditions and identify risk factors which promote or prevent their occurrence. An example of such a cohort study is one on acute respiratory infection. Surveys serve many functions--providing data for planning and evaluation, promoting community awareness of health issues, and addressing basic research questions. The KHAS is one of several surveys launched over the past several years which jointly will begin to provide a circumpolar perspective on the health of Inuit people.

Adolescent↗

Screening with total cholesterol: determining sensitivity and specificity of the National Cholesterol Education Program's guidelines from a population survey.

The objective of the study was to determine the sensitivity and specificity of the National Cholesterol Education Program (NCEP) guidelines in identifying at-risk individuals for hypercholesterolemia, using population-based data from the Manitoba Heart Health Survey (MHHS). The MHHS surveyed a representative sample of adult residents of the province of Manitoba, Canada, aged 18-74 (n = 2792), 2212 of whom underwent complete lipoprotein analyses: total cholesterol (TC), high-density (HDL) and low-density (LDL) lipoprotein cholesterol, and triglycerides (TG) after overnight fasting. Following NCEP criteria for risk categories, 618 individuals could be considered as "at risk" based on their HDL and/or LDL levels. However, if the NCEP algorithms were followed, i.e. initial screen for TC only, and determination of HDL and LDL for selected individuals with borderline and high TC, only 438 of the total "at risk" individuals would have been identified (sensitivity = 71%). 1203 of 1594 individuals with acceptable HDL and LDL levels were not considered "at risk" on screening (specificity = 76%). If "at risk" status was determined solely on LDL criteria, the NCEP guidelines result in a higher sensitivity (94%) and comparable specificity (76%). However, when only HDL criteria were used, the sensitivity and specificity declined to 38% and 63% respectively. Compared to a simulated screening study based on the Lipid Research Clinic data reported by Bush and Riedel (1991) the estimates of sensitivity from the MHHS were high. Current NCEP guidelines appear to balance optimally the sensitivity and specificity for selecting individuals based on TC levels for further complete lipoprotein analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Risk of clinical diabetes in a northern Native Canadian cohort.

A cohort of 630 non-diabetic adult Cree and Ojibwa Indians aged 20-64 from 6 remote communities in northern Manitoba and Ontario were followed for 46-63 months. During this period, 22 new cases of clinical diabetes were registered, an incidence density of 8.0/1000 person-years (95% confidence interval 5.8-10.3). Compared to the few published incidence studies, the rate in this population is slightly higher than the "general" North American population but still far below that of the extremely high risk groups such as Pima Indians and Nauruans. On multivariate analyses, fasting plasma glucose (FPG) level and body mass index (BMI) at baseline were significant independent predictors in a multiple logistic regression model that also contained age, sex, total cholesterol, HDL-cholesterol, triglycerides, hypertensive status, waist/hip ratio and subscapular/triceps skin-fold ratio. These associations are in accordance with current knowledge of the pathogenesis of non-insulin-dependent diabetes. This study indicates that a longitudinal follow-up study of a cohort of non-diabetic Native Canadians in remote communities is feasible. Useful data on the etiologic role of various risk factors can be generated which may be used in the planning of intervention programs in the control of this emerging health problem.

Adult↗

Registries and administrative data: organization and accuracy.

In this article the organization and accuracy of the population registry and administrative data base in Manitoba, Canada are discussed. The overall data management strategy and a framework for analyzing the accuracy of such data are presented. The generally high quality of the Manitoba registry file (necessary to track individuals over time) and the hospital claims is supported by comparisons with other data sources. Hospital claims' main quality problems concern the reliability of certain secondary diagnoses and the level of aggregation necessary for reasonable agreement with other data collection methods (such as chart reviews). Finally, some of the research possibilities associated with population registries and administrative data are outlined.

Adolescent↗

Amelioration of antioxidant enzyme suppression and proteinuria in cyclosporin-treated puromycin nephrosis.

The effect of cyclosporin (CS) on intrinsic glomerular level of antioxidants in puromycin aminonucleoside (PAN) nephrosis was examined. A single intravenous dose of PAN (50 mg/kg body weight) given to Sprague-Dawley rats resulted in marked proteinuria. Ten days after PAN injection, the rats were treated with daily intraperitoneal injection of CS (10 mg/kg body weight/day) for 10 days. PAN-treated rats without CS treatment (PAN rats) had significantly lower activities of glomerular superoxide dismutase (SOD) and catalase (CAT) than normal rats (p < 0.05, respectively). When compared with PAN rats, CS-treated PAN rats had significantly less proteinuria and higher activities of glomerular SOD and CAT (p < 0.01 and p < 0.05, respectively). Significant elevation of glomerular malondialdehyde (MDA) level characteristic of PAN rats was absent in CS-treated PAN rats. Moreover, segmental sclerosis with capsular adhesion, hyalinosis, epithelial cell foot process fusion and microvillous transformation seen in PAN rats were apparently attenuated in CS-treated PAN rats. When compared with normal rats, rats receiving CS only had a significantly higher CAT activity and MDA level (p < 0.01 and p < 0.05, respectively). Assessment of glomerular reduced glutathione revealed no significant differences among PAN rats, CS-treated PAN rats, normal rats, and rats receiving only CS. These data indicate that glomerular antioxidant enzyme activities are modulated by CS.

Animals↗

Cardiovascular diseases in a Canadian Arctic population.

OBJECTIVES: The purpose of this study was to review cardiovascular mortality, morbidity, and risk factors in the multiethnic population of the Northwest Territories, Canada. METHODS: We analyzed death certificates and hospital records, and used a community health and examination survey. RESULTS: The age-standardized mortality rate for ischemic heart disease (but not for other heart diseases or stroke) among the Northwest Territories population was lower than among the Canadian population. Among the indigenous Inuit/Eskimos and Indians, the age-standardized mortality rate for all circulatory diseases was lower than Canadians. Among Indian women, the rate approached the Canadian rate and exceeded that of Inuit and non-Natives. Compared with residents of Manitoba, Northwest Territories Inuit adults had a higher prevalence of smoking in all age-sex groups. Obesity was prevalent among older Inuit women and hypertension among young Inuit men. Except for women aged 25 to 44, the total cholesterol and triglyceride levels among Inuit were lower than or not different from Manitoba residents. Relatively high levels of high-density lipoprotein were found in older Inuits. CONCLUSIONS: The epidemiologic pattern of cardiovascular diseases in Arctic Canada differs from that among non-Native, southern Canadians. Rapid sociocultural changes may alter the situation, and health agencies must anticipate such transitions and intensify culturally appropriate control programs.

Canada↗

Diminution of antidiuretic and natriuretic response to arginine vasopressin in rats with five-sixths nephrectomy.

Adult male Sprague-Dawley rats subjected to five-sixths nephrectomy (5/6NX) and uninephrectomy (UNX) were tested for their responses to arginine vasopressin (AVP) at a rate of 100 microunit/kg/min during water diuresis. Blood and timed urine samples were collected for determination of inulin, creatinine, urea nitrogen, osmolality and sodium. The levels in plasma of urea nitrogen and creatinine were greater in 5/6NX than in intact or UNX group. Antidiuretic response to AVP diminished with intensity of renal ablation. The increased urine osmolality in response to AVP was also found to attenuate with varying degrees of nephrectomy. Marked natriuretic response to AVP was observed in intact and UNX rats but not in the 5/6NX group. In conclusion, diminished antidiuretic and natriuretic response to AVP in rats with 5/6NX might be the results of alteration of lower segments of remnant nephron secondary to uremia following extensive renal ablation.

Animals↗

The effect of mannitol on antidiuretic and natriuretic actions of ADH in rats.

The effect of mannitol and glucose on antidiuretic and natriuretic actions of ADH was investigated in water-loaded, male Sprague-Dawley rats anesthetized with sodium pentobarbital (5 mg/100g). Water diuresis was induced and sustained by continuous intravenous perfusion of hypotonic solution containing 0.3% NaCl, 1.67% glucose, 1.2% ethanol and sufficient inulin at a constant rate 150 microliters/min. Arginine vasopressin at a single dose 0.1 ng/100g was tested twice in the phase of water diuresis and in the phase of water diuresis plus mannitol osmotic diuresis. Urine samples were collected at ten-minute intervals. Three doses of mannitol (5.18, 3.63, 1.81 mumol/min/100g) were given into the right renal artery in three groups of experimental rats, respectively. Administration of mannitol did not alter renal inulin clearance but increased urine flow and excretion of sodium from experimental kidney. Our findings show that mannitol reduced antidiuretic response to ADH in the experimental kidney. This reduction was related to intraarterial mannitol doses. Local administration of mannitol increased natriuretic action of ADH in the experimental kidney. However, a small dose (1.81 mumol/min/100g) of mannitol did not increase natriuretic action of ADH. Saline and glucose (5.23 mumol/min/100g) were also infused intra-arterially to replace mannitol. The effect of saline on antidiuretic and natriuretic responses to ADH was found to be insignificant. Glucose reduced antidiuretic response to ADH as mannitol did but failed to alter natriuretic response to ADH as saline did. We conclude that mannitol does positively affect antidiuretic and natriuretic actions of ADH. Glucose has similar effect but much less than mannitol.

Animals↗

Adult dental health in the Keewatin.

In 1990, as part of a major health status assessment, a dental survey was carried out on a 20 per cent random sample of the adult population in the Keewatin region of the Northwest Territories. A 73 per cent response rate was obtained. Of the 397 people examined, 334 (88 per cent) identified themselves as Inuit. More than 20 per cent of the respondents were edentulous, including 10 per cent of those 18 to 34 years old. The median DMFT was 24 for all respondents and 21 for dentulous respondents. There was a significant difference between Inuit and non-Inuit respondents, which was most marked in the 18 to 34 year old age group (mean DMFT 22.1 versus 15.6, p < .001). The proportion of filled to decayed and filled surfaces (F/DF) was 50 per cent. Periodontal disease was common and increased with age. More than 73 per cent of the dentate individuals had gingival bleeding at one or more sites. Very few were free of calculus. Mean pocket depth increased with age (1.3 mm at 18-34 years of age, rising to 2.3 at 55 plus, p < .001). Sixty per cent of adults needed at least one restorative procedure, 68 per cent needed prophylaxis, and 45 per cent needed periodontal treatment. Men required more treatment of all types than women. The results of this study confirm the clinical impression that dental disease is rampant among the Inuit population. There are major needs for both preventive and treatment services.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗