Population awareness and control of hypertension and hypercholesterolemia. The Atherosclerosis Risk in Communities study.

BACKGROUND: A national program for hypertension detection and control was implemented in the 1970s, whereas a similar program for control of hypercholesterolemia has been implemented in recent years. We studied the levels of awareness, treatment, and control of these conditions in US population samples during a 3-year period (1987 to 1989). METHODS: The levels of awareness, treatment (by medication), and adequate control of hypertension (systolic blood pressure, > or = 140 mm Hg; diastolic blood pressure, > or = 90 mm Hg; or antihypertensive medication) and hypercholesterolemia (serum cholesterol level, > or = 6.21 mmol/L [> or = 240 mg/dL], or lipid-lowering medication) were studied among participants in the baseline examination of the Atherosclerosis Risk in Communities Study, including 15,739 individuals aged 45 to 64 years. RESULTS: Eighty-four percent of the hypertensive subjects and 42% of the hypercholesterolemic subjects were aware of their conditions. Overall, 50% of the hypertensive subjects and only 4% of the hypercholesterolemic subjects had their conditions both treated and controlled. Rates of hypertension prevalence, awareness, and control remained stable during the 3-year study period. Hypercholesterolemia prevalence decreased from 30% in 1987 to 25% in 1989; its awareness increased from 31% to 50% during the same period. Hypertensive women were more likely than hypertensive men to be aware and treated, whereas hypercholesterolemia awareness was higher in men than in women. Hypertension awareness was highest in black women, but black hypertensive subjects were less likely than whites to be treated and to have their hypertension controlled. Black hypercholesterolemic subjects were less likely to be either aware or treated. CONCLUSIONS: After the recent implementation of the National Cholesterol Education Program, the levels of awareness, treatment, and control of hypercholesterolemia are improving at a high rate, although they are still substantially lower than those for hypertension. Further improvement is necessary, particularly among certain population groups, such as blacks.

Effects of metals on Legionella pneumophila growth in drinking water plumbing systems.

An investigation of the chemical environment and growth of Legionella pneumophila in plumbing systems was conducted to gain a better understanding of its ecology in this habitat. Water samples were collected from hospital and institutional hot-water tanks known to have supported L. pneumophila and were analyzed for 23 chemical parameters. The chemical environment of these tanks was found to vary extensively, with the concentrations of certain metals reaching relatively high levels due to corrosion. The effect of various chemical conditions on L. pneumophila growth was then examined by observing its multiplication in the chemically analyzed hot-water tank samples after sterilization and reinoculation with L. pneumophila. L. pneumophila and associated microbiota used in these experiments were obtained from a hot-water tank. These stains were maintained in tap water and had never been passaged on agar. The results of the growth studies indicate that although elevated concentrations of a number of metals are toxic, lower levels of certain metals such as iron, zinc, and potassium enhance growth of naturally occurring L. pneumophila. Parallel observations on accompanying non-Legionellaceae bacteria failed to show the same relationship. These findings suggest that metal plumbing components and associated corrosion products are important factors in the survival and growth of L. pneumophila in plumbing systems and may also be important in related habitats such as cooling towers and air-conditioning systems.