Blood pressure in Jamaican children: relationship to body size and composition

Blood pressure levels in adults and children are related to body size and composition, but some of these relationships are unclear and they have been incompletely described in the Jamaican population. In a cross-sectional survey of 2,332 school children (6-16 years old; 1,046 boys, 1,286 girls), we measured systolic and diastolic blood pressure and pulse rate, and explored their relationship to weight, height, and waist, hip and mid-upper arm circumferences. The effect of these and other derived measures of body composition on blood pressure was explored in univariate and multivariate analysis. Blood pressure increased with age in both boys and girls, although the increase was greater for systolic than for diastolic blood pressure. The increase of systolic blood pressure among boys continued after age 11 years, but that for girls levelled off. Height and weight were the major predictors of blood pressure, but were highly correlated with each other and with all measures of body composition. Age, height and height-sex interaction explained 11.4 percent of systolic blood pressure variation, and the largest incremental contribution to this model was provided by the addition of body mass index or hip circumference, each explaining an additional 2.6 percent of the variance. Lean body mass made a larger contribution to blood pressure than percent fatness. Blood pressure in Jamaican children rises with age and this rise may be steeper in boys than girls. Blood pressure variation is significantly related to several measures of body composition including measures of fatness and fat free masses.(AU)

Comparison of the effectiveness of a beta blocker (Atenolol) and a diuretic (Chlorthalidone) in black hypertensive patients

A double-blind crossover trial of atenolol and chlorthalidone was done in black Jamaican hypertensive patients. After an initial four weeks of single drug therapy, the beta blocker and thiazide diuretic were used in combination. Chlorthalidone at a daily dose of 25 mg produced a significant (p<0.05) fall in the mean systolic and diastolic pressures (19.4 mm Hg and 12.2 mm Hg respectively); atenolol produced a significant fall in th ediastolic blood pressure (6.5 mm Hg); and combination therapy produced a reduction systolic and diastolic blood pressures (27.8 mm Hg and 17.8 mm Hg, respectively). The study showed that combination therapy using a low dose of thiazide diuretic and a beta blocker was synergic, but that a thiazide was more effective than a beta blocker in lowering the blood pressure in black hypertensive patients. (AU)

The response of malnourished babies to cold

Twelve malnourished Jamaican children, aged 4-6 months, were studied before and after treatment, to see whether malnutrition impared their response to cold. When they were studied in the post-absorptive state and in a neutral thermal environment, they had a lower rate of oxygen consumption per kg body weight, a slower pulse rate, lower body temperatures, lower R.Q., and evidence of a smaller peripheral blood flow on admission to hospital than they did after recovery. The malnourished children failed to increase their heat production above resting levels at 25§ C, and their rectal temperature fell at a rate of 1§ C/hr in spite of a further decrease in peripheral circulation. When they had recovered they maintained their body temperature within the normal range on exposure to this temperature, while increasing their heat production by 20 percent. The thermogenesis was apparently of the non-shivering type. There was evidence of increased metabolic activity in the interscapular brown fat pad at 25§ C both on admission and before discharge. In the malnourished children this activity was not sufficient to produce a measurable increase in total oxygen consumption. Interscapular brown fat was examined at autopsy in thirteen malnourished and fifteen well nourished children aged 1-24 months. Lipid depletion was found in this tissue in the former but not in the latter. This may explain the impared response of the malnourished child to cold. (AU)

Some clinical aspects of subarachnoid haemorrhage

Two hundred and forty-six cases of "subarachnoid haemorrhage" admitted to a general hospital over a five year period (1952-56) are presented, of which 190 were treated "medically" and 56 "surgically". The results are compared. If patients dying within the first 24 hours of admission to hospital are excluded, the comparison between those treated medically and surgically is quite favourable towards "conservatism", confuting the generally quoted figures which usually have a decided bias towards surgery and are too often derived from selected groups. Patients with persisting symptoms and signs, or with a secondary rise in pulse rate and recurrence of signs and symptoms should be promptly investigated by angiography and sent to surgery. Non-ganglion blocking hypotensive drugs should be considered in the hypertensive subject. A plea is made for a more rational approach to the problem, particularly in centres where they are admitted to the wards of a general hospital. (AU)