SUMMARY Although the association between body weight and blood pressure is irrefutable, body fat mass and blood pressure level may not necessarily be directly related. To clarify the relative contribution of fat mass to blood pressure level, we analyzed data on 399 adults consecutively entering a weight control program. Although most subjects were notably overweight (mean ideal body weight 177%), the population represented a wide spectrum of body weights and blood pressure levels. Study parameters included body fat mass (by total body water, 40 K, and Steinkamp formula), lean body mass, body build (chest to height ratio), fat cell number and size from bilateral buttock biopsy specimens, upper fat pattern by arm to thigh circumference ratio, and central fat pattern by subscapular to triceps skinfold ratio. Our results concurred with previously noted correlations between obesity and blood pressure (as mean arterial pressure): weight (r = 0.44), percentage of body fat (r = 0.19), and absolute fat mass (r = 0.38; all p < 0.01); however, lean body mass, age, and body build correlated highly with both fat mass and mean arterial pressure, thereby confounding this relationship. Multivariate analysis was performed to evaluate the relative contribution of fat mass to mean arterial pressure in the presence of these and other potentially confounding variables. Lean body mass, age, body build, and an upper body fat pattern were found to contribute significantly to the variation in mean arterial pressure (p < 0.01). In their presence, percentage of body fat, absolute fat mass, central fat pattern, fat cell characteristics, and age of onset of obesity did not significantly improve the predictability of mean arterial pressure. Thus, blood pressure level may be related to the aforementioned correlates of obesity and to body fat pattern rather than to fat mass per se. (Hypertension 7: 578-585, 1985) KEY WORDS • obesity, blood pressure • lean body mass • fat pattern • body build fat cell number and size • weight • hypertension C ONSIDERABLE epidemiological and clinical evidence exists to support an association between obesity and hypertension. The increased prevalence of obesity among hypertensive subjects' and hypertension among the obese 2 is well documented. In addition, prospective trials

Bacterial cultures were made on tube-feeding formulas provided to 35 unselected adult patients on termination of the infusion. Bacteria were counted and identified using routine procedures. Formulas were classified as nonmanipulated, manipulated, or locally prepared. Medical records were reviewed to determine if diarrhea was present during the period that included 2 days on either side of the sampling day. A significant association was observed between the extent of bacterial contamination and the presence of diarrhea (p = 0.027). Locally prepared and manipulated formulas contained a significantly greater number of organisms when compared to nonmanipulated formulas (x2 = 17.81, p less than 0.001). Counts for two baseline and four termination cultures on locally prepared formulas exceeded the acceptable limit for coliform organisms in pasteurized milk according to public health standards. Eight additional cultures on commercial feeding formulas which were presumably sterile initially, exceeded these standards at the end of the administration period. Thus 12 of 35 formulas (34%) would not meet public health standards applicable to pasteurized milk. Use of sterile nonmanipulated formulas in a closed administration set is recommended, along with routine, periodic bacteriologic surveillance of enteral feeding programs.

Dietary calcium, magnesium, and polyunsaturated and saturated fat have each been implicated as being important factors in the development and treatment of hypertension. Although the mechanisms underlying the relationship between calcium and blood pressure are not clearly defined, calcium supplementation may be effective in lowering blood pressure in certain calcium sensitive subgroups. Dietary polyunsaturated fat intake as a source of linoleic acid may be important in the production of prostaglandins, which are known to modify blood pressure levels. Available evidence indicates that an increased intake of polyunsaturated fat relative to saturated fat may have a hypotensive effect in individuals with borderline hypertension. The mechanisms by which magnesium modifies blood pressure are thought to be both direct and indirect, probably interacting with other electrolytes known to affect vascular smooth muscle tone such as sodium, potassium, and calcium. There is insufficient information from human studies to conclude that magnesium supplementation will lower blood pressure levels.

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