What do young adolescent New Zealanders eat? Nutrient intakes of a nationwide sample of form 1 children.

AIM: To determine the nutrient intakes of a nationwide sample of form 1 children (aged 10-11 years), and to identify possible areas of nutritional concern. METHOD: Ten form 1 classes (322 children) were chosen as a nationally representative but nonrandom sample. A 24-hour dietary record was used to obtain quantitative information on all food and beverages consumed. Mean daily intakes were compared with Australian recommended dietary intakes (RDIs) for ages 8 to 11 years. Mean percentage contributions made by selected macronutrients to total energy intake, were compared to targets set for adult New Zealanders. RESULTS AND DISCUSSION: The final sample comprised 251 children (114 boys, 137 girls) aged 10 to 11 years. Mean energy intake was 8.32 MJ/d (boys) and 7.97 MJ/d (girls). These intakes were within the Australian recommended range for 10 to 11 year olds. Snacks contributed a mean of 30 percent to the daily energy intake of this sample. The mean percentage of daily energy from total fat was 36% (boys) and 35% (girls), close to the target set for adult New Zealanders. However, polyunsaturated fatty acids (PUFA) provided only 4% of mean daily energy compared to the 8% recommended for adults. Sugar intake was considered too high, with total sugars contributing one quarter of daily energy. This group would probably benefit from increased consumption of complex carbohydrate including fibre, and less refined sugar. Nearly half of the girls sampled had a calcium intake less than 70% of the Australian RDI. This result is of concern with respect to maintaining positive calcium balance for achievement of peak bone mass. Mean sodium intake was high at approximately 100 mmol/d, despite no information on salt added during cooking and before eating. Intake of zinc and vitamin B6 was considered to be too low with over one-third of the sample consuming less than 70% of the Australian RDI.

Changes in clinical characteristics and drug treatment of hypertension over 40 years at the Dunedin Hypertension Clinic.

The clinical characteristics of the 4,170 hypertensive patients referred to the Dunedin Clinic from 1950 to 1989 have been compared for eight successive 5-year periods. A gradual decrease in the severity of referred hypertension and an increase in the proportion of patients already on treatment at the time of referral (currently 50%) were noted. For male patients, mean +/- SD initial lying blood pressure was 179 +/- 27/116 +/- 19 mm Hg in 1950-1954 and 158 +/- 25/91 +/- 14 mm Hg in 1985-1989. Corresponding prevalence data for target organ damage among male patients were retinal grade 3 or 4, 49% and 3%; cardiomegaly on chest radiograph, 60% and 26%; electrocardiogram left ventricle strain pattern, 28% and 3%; and serum urea levels greater than 10 mmol/L, 16% and 5%, respectively. For women there was a similar trend. The number of patients on drugs in each of nine categories and the percent use of each drug category for each year during 1950-1989 was recovered from computerized data files. The percentage peak usage of ganglion blockers was in 1950-1958, adrenergic neuron blockers in 1963-1970, centrally acting drugs in 1965-1968, diuretics in 1960-1982, beta-blockers in 1974-1987, alpha-blockers in 1980-1987, and angiotensin converting enzyme inhibitors and calcium antagonists in 1989. The diuretics have been the most enduring drugs, followed by the beta-blockers.

Risk predictors in treated hypertension.

The data for patients referred to the Dunedin Hypertension Clinic (975 men, 1,348 women) between 1953 and 1977 have been examined by the Cox proportional hazards method for significant age-corrected predictors of 8-year cardiovascular and total mortality. For men, some significant predictors were systolic and diastolic blood pressure (BP), indices of target organ damage (heart and eyes) and smoking at presentation, and achieved BP and serum cholesterol at follow-up. For women, serum cholesterol, diabetes, target organ damage (heart and eyes) and smoking at presentation, and achieved BP level at follow-up were predictors. Relative risk for total or cardiovascular mortality was increased in both sexes most by smoking and by increased levels of achieved BP.

Eight-year survival study of treated hypertension at the Dunedin Hypertension Clinic 1953-1977.

The 8-year follow-up data of consecutive 5-year cohorts of hypertensive patients starting treatment at the Dunedin Hypertension Clinic between 1953 and 1977 have been analysed. There were 975 men and 1348 women. Since 1953 treatment has been initiated in progressively milder forms of hypertension, and blood pressure has been controlled at progressively lower levels. The mean age at presentation for both men and women was 51 years. The mean age at death and the cause of death did not differ significantly among the cohorts, but the percentage incidence of events (including death) over the 8-year follow-up decreased significantly (P less than 0.0001) from 76% for males and 57% for females in the 1953-1957 cohort, to 33% for males and 25% for females in the 1973-1977 cohort. Survival was poorest in the earlier cohorts, especially the 1953-1957 cohort. The 8-year relative survival of treated hypertensives compared with the general population of New Zealand improved over time and was about 0.9 for the 1973-1977 cohort, a little less for males and a little more for females.

The Spielberger Anger Expression Scale: some psychometric data.

Some general population norms for the Spielberger, Johnson et al. (1984) Anger Expression Scale (AX) are reported for a sample of over 1000 adults tested in a general health survey of a New Zealand community. Factor analysis confirmed the independence of the Anger/In and Anger/Out subscales, and the measure was found to have satisfactory levels of reliability.

What do middle-aged New Zealanders eat? A dietary survey in 50-54 year olds in south Canterbury and north Otago.

Information on diet was obtained from a random sample of 50-54 year olds in October 1985 when a health survey was conducted in the Timaru health district. This survey formed part of the international cardiovascular diseases and alimentary comparison (CARDIAC) study. A seven-day dietary history was obtained from 99 male and 82 female participants who were not taking any antidiabetic or antihypertensive medication. The median daily energy intake was 10.5 MJ for the men and 6.3 MJ for the women. The median daily total fat intake for men and women respectively was 103 g and 68 g. The median ratio of polyunsaturated to saturated fatty acids was low, 0.19 for the men and 0.18 for the women. Total fat contributed 37.5% to energy intake of men and 38.5% to energy intake of women and alcohol contributed 5.1% for men and 2.1% for women. Mineral and vitamin intakes were generally satisfactory. A substantial proportion of the participants, particularly women, claimed to have decreased their total food, fat, salt, meat, eggs and milk intakes and to have increased their vegetable and fish consumption.

Effects of arm position and support on blood-pressure readings.

The effect of changes in arm position and of arm support on blood-pressure readings was assessed in 240 hypertensive outpatients with the arm in various positions. Mean blood pressure was lowest with the arm supported at heart height and highest with the arm dependent, the difference averaging 8 mmHg for both systolic and diastolic pressure and being greater for men than for women. Arm support at heart height lowered blood pressure only slightly, when compared to that taken on the unsupported arm at heart height. These findings suggest that an increase in apparent blood pressure associated with arm dependency during the recording can spuriously increase the height of the blood pressure and the prevalence of hypertension. In the individual patient it may lead to unnecessary increase in antihypertensive dosage. Whenever standing blood pressure is quoted, arm position should be stated.

Self-reported anger intensity and blood pressure.

During a health survey of a New Zealand community, two S-R inventories measuring responsiveness to anger and to anxiety provoking situations were administered to 1127 adults. With age treated as a covariate, no association was found between scores on these measures and blood pressure.

Intracellular cations and transmembrane cation transport in essential hypertension: the importance of controlled clinical observations.

We measured Na+, K+ and total Ca2+ concentrations as well as first order efflux rate constants for Na+ and Ca2+ in red cells from 22 patients with untreated essential hypertension and 22 normotensive control subjects. Both groups were individually and prospectively matched for age, sex and weight. Intracellular Na+ and K+ were also measured in a separate population consisting of 31 hypertensive patients and 41 normotensive subjects who were not matched. In order to test for possible plasma inhibitors of Na+ or Ca2+ transport in hypertension, Na+ and Ca2+ efflux rate constants in 15 paired patients were measured in red cells which were incubated in either homologous or paired plasma. Intracellular Na+ and K+ concentrations and Na+ and Ca2+ efflux rate constants were similar in the matched subjects. Significant positive correlations were found between intracellular Na+ and body weight (r = 0.27, P = 0.041) and between intracellular K+ and age (r = 0.29, P = 0.028). In the unmatched population intracellular Na+ correlated significantly with age (r = 0.25, P = 0.029) and was significantly increased in hypertensive patients. This difference was due wholly to increased intracellular Na+ in hypertensive females. After correction for age and weight, intracellular Na+ was similar in both hypertensive and normotensive subjects. Intracellular K+ did not differ between these groups but was significantly lower in males. Intracellular Ca2+ was similar in the matched groups after correction for age and weight, but the regression equations containing age and weight as independent variables were significantly different in hypertensive and normotensive subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of age, sex and weight on measurements of intracellular Na+ and K+ in essential hypertension.

Na+ and K+ concentrations were measured in red cells from 22 patients with untreated essential hypertension and 22 normotensive control subjects who were individually and prospectively matched for age, sex and weight and in a separate population of 31 hypertensive patients and 41 normotensive subjects who were not so matched. Intracellular Na+ and K+ concentrations were similar in the matched subjects. Significant positive correlations were found between intracellular Na+ and body weight (r = 0.27, P less than 0.041), and between intracellular K+ and age (r = 0.29, P less than 0.028). In the unmatched population, intracellular Na+ was significantly increased in patients with hypertension and was correlated significantly with age (r = 0.25, P less than 0.017). After correction for age, intracellular Na+ was similar in both hypertensive and normotensive subjects. Age-corrected intracellular K+ was similar in both hypertensive and normotensive groups but was significantly lower in male subjects. These results highlight the importance of matching study groups for age, sex and weight when studying possible abnormalities in cell ionic composition in hypertension. False positive results may arise if study groups are not matched for these characteristics. Red cell Na+ and K+ are not altered in essential hypertension.

Body sodium in rats: response to DOCA, adrenalectomy, changes in salt intake, and a salt load.

Body Na was studied by an isotope method in rats on Na-free diet plus a choice of H2O and 0.5% or 0.1% NaCl. Two groups (1 on 0.5%, 1 on 0.1% NaCl) had Silastic deoxycorticosterone acetate (DOCA) implants, two similar groups were sham operated, and a fifth group (on 0.5% NaCl) underwent adrenalectomy (ADX). Saline consumption increased in DOCA-treated and ADX rats. Body Na was increased by DOCA and by drinking 0.5% NaCl compared with 0.1% NaCl. Body Na after intraperitoneal NaCl loading (which raised body Na 8-10%) and withdrawal of NaCl drinking fluids was analyzed by use of the model y = Ae-a(t-d) + Be-bt, where y is body Na at time t and d is delay before fast rate constant a is established; d was greater on the lower Na intake. Rate constant a was not reduced by chronic DOCA treatment. Coefficient B of the slow exponential, representing the basal level to which body Na falls on zero Na intake, and equivalent to Hollenberg's "set-point," was higher in DOCA-treated rats. This analysis makes use of Hollenberg's set-point concept, but the findings suggest that the set-point is related to mineralocorticoid activity and is thus presumably variable.

The relationship between blood pressure and personality in a large unselected adult sample.

As part of a general health survey of a small New Zealand town, the Crow-Crisp Experiential Index, the State-Trait Anxiety Inventory, a shortened version of the Hostility and Direction of Hostility Questionnaire, and the Zung Self-rating Depression Scale were administered to 1173 subjects over the age of 15. Blood pressure was moderately correlated with age and Quetelet's Index, a measure of obesity. Low but significant correlations were found between Somatic Anxiety, Hysteria, and the Urge to Act-out Hostility scale. However, when effects of age were controlled for, in a series of multiple regression analyses, the correlations with psychometric test scores were no longer significant. This study confirms several previous reports that neuroticism, anxiety, depression, and hostility are of little significant in predicting levels of blood pressure in the general population.

Effects of DOCA and salt intake on body sodium, fluid intake, blood pressure and excretion of a sodium load in rats.

Body sodium was measured repeatedly by a whole-body counting method (22Na) in control and deoxycorticosterone acetate (DOCA)-treated Wistar rats taking a sodium-free pelleted diet and drinking a choice of H2O and either 0.5% NaCl or 0.1% NaCl (n = 11 per group, four groups). Body sodium was higher in DOCA-treated than in control rats and higher in rats on 0.5% NaCl than in those on 0.1% NaCl. These differences persisted even when all sodium intake was stopped. An intraperitoneal NaCl load was excreted at least as rapidly by the DOCA-treated as by the control rats. Commencement of excretion was slower in the rats on 0.1% NaCl than in those on 0.5% NaCl. It is concluded that DOCA raises the basal level of body sodium but does not slow down the excretion of sodium in the body in excess of the basal level.

Alcohol consumption and blood pressure in a New Zealand community study.

The relationship between stated alcohol consumption and blood pressure was investigated in 901 adults who participated in a multiphasic health survey in Milton in May 1981. Subjects taking oral contraceptives or drugs which could lower blood pressure were excluded. Eighty-five percent of men and 52% of women reported taking some alcohol at least once a month. The percentage using alcohol was highest (96%) in men aged 20-29 years. The reported mean weekly intake by users was 171 g for men and 56 g for women. After adjustment for age and body mass index, there was a positive association between alcohol intake and blood pressure for men. The mean systolic and diastolic pressures of male heavy alcohol users (300 g or more alcohol per week) were, respectively, 9.8 and 8.9 mmHg higher than those of male non-drinkers. No relationship between alcohol intake and blood pressure was found in the women.

Evidence against a circulating ouabain-like transport inhibitor as a cause of increased red cell sodium in essential hypertension.

Red cell sodium and potassium concentrations, and total ouabain-sensitive and ouabain-insensitive first order red constants for sodium efflux, were measured in 15 patients (11 female, 4 male) with essential hypertension (162 +/- 14/99 +/- 7 (s.d. mmHg) and 15 normotensive control subjects (117 +/- 17/64 +/- 10 mmHg) individually matched for age (45.8 +/- 10 versus 45.7 +/- 10 years, respectively, sex, weight (68.6 +/- 16.1 versus 64.7 +/- 11.2 kg) and blood group. To test for possible plasma inhibitors of sodium transport in hypertension, total efflux rate constants were measured in red cells incubated in two plasma samples, from either the same or the complementary (paired) subjects, respectively. Intracellular sodium was significantly increased in patients (11.8 +/- 3.45 versus 8.75 +/- 2.48 mmols/l of red cell water; P = 0.023). Intracellular potassium and total and ouabain-sensitive sodium efflux rate constants, were similar in both groups. Sodium efflux was similar when cells were incubated in the homologous and complementary plasma samples. Ouabain-insensitive rate constants were decreased in the patients (0.16 +/- 0.08 versus 0.20 +/- 0.05 h-1) but the difference was of borderline significance (P = 0.059). These results confirm the presence of abnormal intracellular sodium concentrations and membrane transport in essential hypertension but are not consistent with the suggestion that the abnormalities are due to a circulating sodium transport inhibitor.

Iodide excretion in a salt-restriction trial.

Twenty-four hour urinary iodide excretion was measured twice, with a four month interval, in 133 individuals who were in a 12-month salt-restriction study in an area where iodine-deficiency goitre was once common and where most household salt is iodised. Half the subjects were salt restricted; their mean 24 h sodium excretion after eight months was 89 mmol for men and 73 mmol for women. Iodide excretion correlated with sodium excretion in the whole group on each occasion. After eight months mean 24 h iodide excretion in the salt-restricted group (men 1.3 SD 0.6 mumol, women 1.1 SD 0.4 mumol) was lower (p less than 0.01) than that in the control group (men 1.8 SD 0.8 mumol, women 1.7 SD 0.8 mumol), but was reasonable in terms of recommended dietary allowances (1.2 mumol, 150 mg). Mean iodide content of local milk was 1.3 mumol/l. Any salt that is used in the home should continue to be iodised. However, it has become unnecessary in this population to use salt (ie, iodised salt) simply in order to avoid iodine deficiency, so long as other foodstuffs continue to contain iodine as at present. As the other sources of iodine may be subject to change, the adequacy of intake of iodine from these sources should be monitored from time to time in samples of the population.

Selenium and risk factors for cardiovascular disease in New Zealand.

Blood selenium (Se) concentrations and glutathione peroxidase (GSHPX) activities were measured in 118 men (39 +/- SD 15 yr) and 112 women (42 +/- 16 yr) randomly selected from the total respondents (1192) to health survey in Milton, a low soil-selenium area in Otago. GSHPx activities were marginally lower for men (11.9 +/- 3.2 units/g Hb) than for women (12.9 +/- 3.8 units/g Hb). Blood, erythrocyte and plasma selenium concentrations were about the same for both sexes and means for all subjects (61 +/- 15; 73 +/- 19; 49 +/- 12 ng Se/ml) were almost identical with a control group of Otago blood donors. No differences in blood levels could be associated with smoking, use of oral contraceptives, arthritis and/or rheumatism, or anti-hypertensive drugs. No relationship was found for the men or women between any of the parameters of selenium status and any of the parameters of risk factors for cardiovascular disease measured in the health survey: age, Quetelet's index, total skinfolds, systolic and diastolic pressure, pulse rate, plasma lipids and lipoprotein lipid concentrations. Moreover no relationship was found for the subgroups (36% group) of men and of women with plasma selenium below 45 ng Se/ml. This study indicates that if selenium is important it does not operate through the risk factors of cardiovascular disease as presently understood.