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Biomedical subjects

W R Leonard

Publications and source records attributed to W R Leonard.

43 records · Page 3Linked to original sources
PubMed1984

Blood pressure in blacks and whites and its relationship to dietary sodium and potassium intake.

The 24-hour dietary intake and blood pressure of 1928 black and 9739 white adults derived from the data sets of the first US National Health and Nutrition Examination Survey (NHANES I) of 1971-1974 were analyzed. Contrary to expectation, the absolute and relative intakes of sodium and potassium in blacks were less than those of whites. However, because the difference in potassium was greater than the difference in sodium, blacks did have a significantly higher sodium/potassium ratio than whites. Blacks had significantly higher blood pressure than whites even when adjusted for differences in sodium/potassium ratio. It is concluded that the higher blood pressure and prevalence of hypertension in blacks does not appear to be a function of an absolutely greater dietary sodium intake, but related to a relatively low intake of potassium. It is possible that blacks have a greater sensitivity than whites to the hypertensinogenic effects of sodium which, coupled with the relatively low dietary intake of potassium, accounts for their increased blood pressure.

Adult↗
PubMed1976

Arizona hinshawii osteomyelitis with antecedent enteric fever and sepsis. A case report with a review of the literature.

A case of Arizona osteomyelitis of the spine which occurred 11 months after an episode of gastroenteritis and enteric fever is presented. As close biochemical and antigenic relative of Salmonella, Arizona infection produces a similar clinical course with gastrointestinal manifestations frequently preceding localized infections by several months. The boney lesion in the present case and in three of the four other cases of Arizona osteomyelitis described in the literature was a chronic inflammation which may have a xanthomatous component. The bone destruction caused by Arizona infection is less severe than that of tuberculosis or pyogenic osteomyelitis. Proposed treatment of Arizona osteomyelitis consists of debridement of the localized infection and long term antimicrobial therapy.

Child, Preschool↗
PubMedDate not supplied

Assessing the influence of physical activity on health and fitness.

Increasing rates obesity and related chronic diseases in the United States and other parts of the world appear to be partly attributable to declining levels of physical activity. Given that adult obesity and chronic diseases often have their origins in childhood, there is a critical need to better understand how activity and fitness levels in childhood and adolescence shape health status in adulthood. The four papers in this series on physical activity draw on several longitudinal studies to examine the relationships between levels of physical activity and health-related fitness in childhood and adolescence to those in adulthood. These studies consistently demonstrate that adult activity levels and associated health outcomes are only modestly correlated with activity and fitness measures from childhood and adolescence. However, it appears that the methodological limitations in measuring activity levels may result in an underestimation of the importance of the influence of physical activity on health. Newer methods of measuring activity and energy expenditure offer to substantially improve our understanding of the influence of activity patterns on human health and fitness. Such information is necessary for promoting lifestyle changes that will reduce the risks of obesity and other chronic diseases.

Adolescent↗
PubMedDate not supplied

Health consequences of postsocialist transition: dietary and lifestyle determinants of plasma lipids in Yakutia.

The rapid social and cultural changes introduced by the collapse of the Soviet Union have resulted in important differences in cardiovascular health for indigenous Siberians. This study investigated diet and lifestyle determinants of plasma lipids in the Yakut, an indigenous Siberian herding population. The study used a cross-sectional design with data on 201 subjects in three urbanized towns and three rural communities in northeastern Siberia. Data on sociodemographic characteristics, dietary intake, and material lifestyle were collected, and lipids were analyzed from venous whole blood. Diet was analyzed using patterns of dietary intake based on principal components analysis of a dietary intake (food frequency) questionnaire. We identified three diet patterns: a traditional subsistence diet, a market foods diet, and a mixed diet. The effect of lifestyle on cardiovascular risk factors was measured using an ethnographically defined lifestyle index, with two orthogonal dimensions: subsistence lifestyle and modern lifestyle. Total cholesterol (TC) and low-density lipoprotein (LDL) were significantly higher among those consuming a traditional subsistence diet of meat and dairy products. A modern lifestyle was associated with lower TC and LDL but higher adiposity and higher risk of obesity. LDL and TC were higher in rural communities and lower in urbanized towns. The significantly higher lipid levels associated with a subsistence diet and indirectly with a subsistence lifestyle indicate the emergence of a significant health problem associated with the social and cultural changes occurring in Yakutia today. These findings underscore the need for dietary modification and promotion of physical activity among those most at risk for cardiovascular disease (CVD). Moreover, these results differ from those commonly seen in "modernizing" populations, in that elements of subsistence lifestyle are associated with an elevated rather than reduced risk of CVD. Such variable responses to lifestyle change emphasize the need to better understand the distinct social and historical events that may influence health changes among populations in transition.

Adiposity↗
PubMedDate not supplied

High-sensitivity C-reactive protein, adiposity, and blood pressure in the Yakut of Siberia.

C-reactive protein (CRP), an acute-phase reactant and marker of inflammatory response, is known to be an important predictor of future cardiovascular mortality, independent of other risk factors. The purpose of this research was to investigate the association between CRP, adiposity, and blood pressure in the Yakut, an indigenous Siberian population undergoing rapid cultural change. We conducted a cross-sectional study of 265 healthy Yakut adults in six villages in rural northeastern Siberia. Plasma CRP was measured by high-sensitivity immunoturbidimetric assay. The median CRP value was 0.85 mg/l, with values for the 25th, 50th, and 75th percentiles of 0.30, 0.85, and 2.28 mg/l, respectively. CRP was positively associated with age (r = 0.19; P = 0.002), but not plasma lipids or smoking status. CRP was associated with measures of central adiposity and characteristics of the metabolic syndrome, particularly in women. We found significantly higher CRP across quintiles (Q) of waist circumference for women (difference = 0.7 mg/l; P = 0.035), but not men (difference = 0.36 mg/l; P = 0.515). CRP was significantly associated with systolic blood pressure in men (difference, Q1 vs. Q5 = 1.1 mg/l; P = 0.044) but not women (difference, Q1 vs. Q5 = 0.03 mg/l; P = 0.713) after adjusting for age, waist circumference, and smoking status. CRP in the Yakut was considerably lower than was reported for other populations. The low CRP levels may be explained in part by a low prevalence of abdominal obesity. Among the Yakut, the high physical-activity demands of a traditional herding lifeway likely play a role through high energy expenditure and maintenance of negative energy balance. Our findings underscore the need for further research on the metabolic activity of adipose tissue, blood pressure, and inflammatory activation in non-Western populations.

Adiposity↗
PubMedDate not supplied

Anthropometric variability in the USA: 1971-2002.

AIM: The study analysed variability in physical stature, weight, and body mass index (BMI) in the USA during 1971-2002. SUBJECTS: Subjects were non-Hispanic Blacks and Whites, 2-74 years of age from the National Health and Nutrition Examination Surveys (NHANES I-III and 1999-2002). METHODS: The coefficient of variation and the standard deviation of the logarithm of stature, weight, and BMI were used to assess anthropometric variability for groups defined by age, race, sex, income, and survey year. Weighted ordinary least squares regressions were used to estimate the effect of socio-economic variables on anthropometric variability. RESULTS: (a) The relation between age and variability in weight or BMI resembles an inverted U, (b) men have lower variability in BMI than women, (c) Blacks and the poor have greater variability in weight and BMI than Whites or than the non-poor, and (d) variability in anthropometric indices increased during 1971-2002. Results were robust to the measure of variability used and to the use of the mean and mean square of the anthropometric indicators as explanatory variables. CONCLUSION: Since anthropometric indices correlate reliably with canonical indicators of well-being (e.g. income), growing variability in anthropometric indices, particularly among the Blacks and the poor, signals growing inequality in quality of life--a worrisome trend.

Adolescent↗