Centralized obesity and cardiovascular disease risk in Mexican Americans.

The association between body fat distribution patterns and cardiovascular disease risk variables (high density lipoprotein (HDL) cholesterol, total cholesterol, diastolic and systolic blood pressures, and fasting blood glucose levels) was sought in a sample of Mexican American adults who were studied during 1981-1983 in Starr County, Texas. In the sample, all diabetics were excluded to see whether centralized obesity carried any risk for cardiovascular disease independent of diabetes. A component of centralized body fat distribution was identified through the use of principal components analysis of five skinfold measurements, which included the upper and lower extremities and trunk areas. The centralized obese were compared with generalized (peripheral) obese and nonobese controls in four subgroups of the population: younger and older adult males and females. The means of all cardiovascular risk variables were in a direction indicating that the centralized obese were significantly at greater risk than nonobese controls (in particular, HDL cholesterol, total cholesterol, and blood glucose levels). The generalized obese differed from the centralized obese in having significantly lower blood glucose levels, and tended to be intermediate between centralized obese and nonobese controls in the other variables. The data confirm that centralized obesity as defined by a linear combination of skinfold measures works in the same way as the waist-to-hip circumference ratio in describing a body build factor which heightens the risk of cardiovascular disease in the obese independent of the clinical diabetic state.

Gallbladder disease epidemiology in Mexican Americans in Starr County, Texas.

The prevalence of gallbladder disease (surgery or complaints) among Mexican Americans in Starr County, Texas, is demonstrated to be some threefold higher than in Framingham, with 13% and 26% of males and females, respectively, over the age of 35 years having the disease. The population aggregation of gallbladder disease in Amerindian groups and those genetically admixed with them (as the present case) is consistent with an underlying genetic mechanism which is further substantiated here by examining relative risks in sibs, offspring, and spouses of individuals with gallbladder disease. It is shown that in females under the age of 45 years, there is evidence for a significant association between gallbladder disease and diabetes beyond that which could be explained by body mass. Significant gallbladder disease by nonlinear age interaction effects was detected for serum cholesterol. The predicted regression lines of cholesterol by age were uniformly lower for individuals with gallbladder disease than those without it except for ages 40-55 years, in which the lines were equal. When coupled with previous results on diabetes, the results presented document the extent to which diabetes and gallbladder disease dominate the health status of Mexican Americans in southern Texas and likely elsewhere.

Diabetes among Mexican Americans in Starr County, Texas.

An increasing body of evidence suggests that diabetes mellitus constitutes a major health burden among the Mexican-American population. For example, county-wide death rates in Texas attributable to diabetes from 1970-1981 range from 2.5-52.0 diabetes deaths per 1000 total deaths with the highest rates generally occurring in counties whose populations are more than 75% Spanish ancestry. To assess the prevalence and morbidity of noninsulin-dependent diabetes mellitus among Mexican Americans, 14% of the Starr County, Texas, population (97% Mexican-American) was randomly sampled. The reference population, sampling strategy, and screening results are described. Age-specific prevalences of diabetes for males ranged from 0% in males aged 15-24 years to 17.6% in those above 75 years of age. Rates for females ranged from 0.4% in those aged 15-24 years to a high of 19.0% in the 55- to 64-year age group. In both sexes, the rates are relatively low for persons under age 45 with a sharp increase in those aged 45-54 years and high rates prevailing in the older age groups. Comparisons of the rates in Starr County to those of the general US population indicate a two- to fivefold greater risk in Starr County. In terms of impact on this community, these results imply that over 50% of individuals older than 35 years are directly affected by diabetes by virtue of their having the disease or by being a first-degree relative of a diabetic.

Disseminated histoplasmosis in an English patient with diabetes mellitus.

Histoplasma capsulatum is not endemic in Britain. We report a case of disseminated histoplasmosis in an English man who had not ventured out of northern Europe for 30 years. The disease presented as painful mouth ulcers and hepatosplenomegaly six months after he had developed maturity-onset diabetes. The origin of the infecting fungus may have been from within the United Kingdom or alternatively it may have existed as an intraoral saprophyte for over 30 years.

Calcium metabolism in cancer. Studies using calcium isotopes and immunoassays for parathyroid hormone and calcitonin.

Studies of calcium metabolism in 38 patients with cancer indicated that: 1) intestinal absorption of calcium was reduced in patients with skeletal metastases and in those with hypercalcemia; 2) calcium-47 space (a measurement of bone turnover rate) was high in the patients with skeletal metastases; 3) hypercalcemic patients had higher urinary and endogenous fecal excretion of calcium than those who were normocalcemic; 4) levels of plasma immunoreactive parathyroid hormone were similar in normo- and hypercalcemic patients, but the levels for a given serum calcium in malignant disease were lower than those in primary hyperparathyroidism; and 5) some patients had elevated calcitonin levels. Hypercalcemia complicating malignant disease is therefore not due to hyperabsorption or diminished excretion of calcium, and a low calcium diet is unlikely to benefit these patients. Measurement of 47Ca space could be of use in monitoring therapy of patients with skeletal metastases, and measurement of plasma parathyroid hormone could be useful in the differential diagnosis of hypercalcemia.

Oestrogen induced hypertriglyceridaemia: role of the adrenal cortex.

The role of the adrenal cortex in the pathogenesis of hypertriglyceridaemia associated with the intake of oral contraceptive agents containing oestrogen has been investigated in rats. Bilateral adrenalectomy reduced the activity of hepatic enzymes regulating lipogenesis (acetyl CoA carboxylase, fatty acid synthetase) and decreased plasma triglyceride concentrations. On the other hand, the administration of high dosage corticosterone induced the activity of hepatic enzymes with consequent elevation in serum triglyceride levels. In animals with intact adrenals the administration of oestradiol: (a) raised plasma triglyceride levels, (b) enhanced the activity of hepatic enzymes, and (c) increased the adrenal cortex:body weight ratio. The effects (a) and (b) were not observed when both adrenals were removed prior to oestrogen therapy. High dosage corticosterone replacement was found to be essential for the oestradiol to produce its effects on hepatic enzymes and plasma triglyceride levels. The results suggest a regulatory role for the adrenal cortex in the homeostasis of plasma triglyceride concentration and that the hypertriglyceridaemia induced by the oestrogen containing preparations might be secondary to alterations in adrenocortical function.

Mode of insulin action.

A unifying hypothesis is proposed for the mechanism of insulin action in adipose tissue. Insulin both induces displacement of Ca++ from a membrane-bound pool and inhibits efflux of the ion, thereby facilitating a rise in intracellular free Ca++ concentration. The former effect could enhance the transport of substrates and ions into the cell, while the latter modulates the activity of some intracellular enzymes to stimulate glycogenesis, lipogenesis, and decrease lipolysis and glycogenolysis. The calcium ion might act as the missing second messenger for insulin action.