Body mass index and depressive symptoms in primary care settings: examining the moderating roles of smoking status, alcohol consumption and vigorous exercise.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Depressive symptoms and obesity are highly prevalent in primary care settings. Depressive symptoms and obesity are positively related; as body weight increases, individuals are more likely to display depressive symptoms. WHAT THIS STUDY ADDS: This study examines the moderating roles of health behaviours (alcohol use, smoking status and vigorous exercise) on the relationship between body mass index and depressive symptoms. Exercise attenuates the relationship between depressive symptoms and obesity. Primary care patients often report multiple health risk behaviours and symptoms, including obesity and depressive symptomatology. This study examined the relationship between body mass index (BMI) and depressive symptomatology among primary care patients and tested its moderation by health behaviours. Primary care patients (n = 497) completed self-report questionnaires. Using three multilevel models, we tested the moderation of health behaviours on the BMI-depressive symptoms relationship. After controlling for relevant covariates, BMI was positively related to depressive symptoms. Smokers reported more depressive symptoms (P < 0.01), whereas vigorous exercisers reported fewer (P < 0.001). Alcohol consumption was not related to depressive symptoms (P > 0.05). Only vigorous exercise significantly moderated the BMI-depression relationship (P < 0.05). BMI is positively related to depressive symptoms among patients who do not participate in vigorous activity, suggesting that vigorous activity reduces the risk for depressive symptoms among patients with higher BMI.

Plasma 25-hydroxyvitamin D concentrations are inversely associated with blood pressure of Dahl salt-sensitive rats.

Dietary salt is a contributing factor to the development of hypertension in individuals who are salt-sensitive. The vitamin D endocrine system has been reported to modulate vascular structure and function. Since elderly hypertensive females with low plasma renin activity, typical of salt-sensitivity, had significantly lower 25-hydroxyvitamin D concentrations compared with normotensive elderly and young females, we have used Dahl salt-sensitive and salt-resistant rats fed high (80 g/kg diet) and low (3 g/kg diet) salt diets as models to examine the relationship between salt-sensitivity and 25-hydroxyvitamin D, the precursor of the hormonal form of vitamin D, 1,25-dihydroxyvitamin D. Plasma 25-hydroxyvitamin D concentrations of salt-resistant rats were unaffected by a high salt diet, but plasma 25-hydroxyvitamin D concentrations of salt-sensitive rats were significantly reduced within three weeks to lower than 25%. There was a negative association between plasma 25-hydroxyvitamin D concentrations of salt-sensitive rats and the number of days that the rats were fed a high salt diet (r = -0.98, P < 0.02) and a positive association between blood pressure and the number of days that the rats were fed a high salt diet (r = 0.97, P < 0.05). An inverse relationship was found between plasma 25-hydroxyvitamin D concentrations and blood pressure (r = -0.99, P < 0.01). Spontaneously hypertensive rats did not have low plasma 25-hydroxyvitamin D concentrations, suggesting that reduction of plasma 25-hydroxyvitamin D concentration might be specific to salt-induced hypertension.

Racial differences in mortality from cardiovascular disease in Atlanta, 1979-1985.

Mortality from cardiovascular disease (CVD) for the period 1979 to 1985 in the Atlanta metropolitan population was reviewed for racial differences. About 28% of the population was black in 1980. Of 22,585 deaths from hypertension, stroke, ischemic heart disease, and atherosclerosis, 78.7% occurred among whites and 21.3% among blacks. Overall, ischemic heart disease accounted for 47.7% of these four types of CVD deaths for both races and sexes. Age-specific and age-adjusted rates were compared. Among these four causes of death, blacks have the greatest excess of deaths from hypertension over whites for both males and females; the excesses were more than 200% when the rates were age-adjusted. The excess risk of death from hypertension occurred for all ages in blacks, with an excess of about 10 times in 30- to 49-year-olds. An excess risk from stroke also occurred in blacks below the age of 75; the risk reversed afterward. The age-specific mortality rates revealed an excess from ischemic heart disease only between the ages of 30 and 59 years and from atherosclerosis between 40 and 59 years of age for black men. This age-related crossover in females did not occur until the age of 75 years for deaths attributed to these causes. These data suggest that blacks were at highest risk for all four causes at younger age groups.

Movement of Entamoeba histolytica trophozoites in rat cecum and colon intact mucus blankets and harvested mucus gels.

Entamoeba histolytica trophozoites were centrifuged into mucus gels harvested from in vivo loops of rat cecum and proximal colon. Frank ameba movement was not detected in the colonic mucus, but attenuated motility was measured in the cecal mucus. The harvested rat cecal mucus had significantly lower apparent viscosity and neutral glycoprotein concentration values than the colonic mucus. A shape factor method was developed to assess the motility of amebae in mucus gels and intact mucus blankets. Shape factor data obtained from harvested mucus gel and intact mucus blanket experiments indicated that such mucus severely attenuated trophozoite movement with the attenuation being greater with colonic than with cecal mucus. Entamoeba trophozoites are known to be able to generate a pseudopod force of 3.3 x 10(-6) Newtons. Latex microspheres of the size range of Entamoeba trophozoites were forced through cecal and colonic mucus gels under gravity. Colonic mucus gels could withstand a force of 3.3 x 10(-6) Newtons while cecal mucus could not, suggesting that the ameba movement that was observed in cecal mucus involved mechanical penetration of the mucus by the ameba pseudopodia and did not require prior gel dissolution by Entamoeba enzymes.

In vitro and in vivo effects of endothelial cell-derived growth factor.

Endothelial cells in culture produce a growth factor with an apparent molecular weight of 10,000 to 30,000 daltons. This material, the endothelial cell-derived growth factor ( ECDGF ), can replace the requirement of 3T3 and smooth muscle cells for exogenous mitogens. ECDGF , added to plasma-derived serum, a platelet deficient preparation of plasma, supports growth of these cells to confluency. Lyophilized preparations of the ECDGF stimulate migration of smooth muscle cells into an in vitro wound. The same material induces an angiogenic response when implanted on the chick chorioallantoic membrane. Thus two requirements of an angiogenic response, migration and proliferation, are supplied by endothelial cell products.

Neovascular responses induced by cultured aortic endothelial cells.

Neovascularization was studied in the chorioallantoic membrane of the chick embryo after implantation of bovine aortic endothelial and smooth muscle cells, Swiss and BALB/c 3T3 cells and human diploid fibroblasts cultured separately on microcarrier beads. Quantitative analysis of neovascularization indicated a 3 1/2-fold increase in the number of blood vessels responding to endothelial cells while smooth muscle cells induced a twofold increase when compared to the response of beads without cells. Skin fibroblasts and Swiss 3T3 cells did not elicit a comparable response. The marked angiogenic response induced by endothelial cells was characterized by a 137% increase in total vessel length and a 35% increase in average vessel area when compared to controls. Two of the properties required for an angiogenesis factor--stimulation of cellular migration and proliferation--can also be demonstrated using endothelial cell-conditioned medium in cell culture systems. Medium from cultured bovine aortic endothelium stimulates DNA synthesis, proliferation, and migration of smooth muscle cells. In addition, conditioned media from both endothelial cells and smooth muscle cells produced an angiogenic response in the chorioallantoic membrane assay, which was comparable to that produced by intact cells growing on microcarrier beads. Similar responses were not evident with medium conditioned by other cell types. These results indicate the potential importance of endothelial cells and endothelial cell products in regulating blood vessel growth.