Predictors of relatives' attendance at a state hospital workshop on schizophrenia

A prospective research design was used to identify patient and family variables that would predict relatives' attendance at an educational workshop on schizophrenia at a state psychiatric hospital. Data were collected from patient charts and telephone interviews with relatives. Thirty-two percent of the 84 invited relatives attended the workshop. Significant predictors of attendance included relatives' proximity to the hospital, previous number of visits with the patient, knowledge about schizophrenia, and familiarity with the National Alliance for the Mentally Ill. The findings suggest that a substantial proportion of relatives of the seriously mentally ill desire information and help in coping with their ill family member. Relatives' participation might be further increased by conducting workshops at more convenient sites and encouraging attendance by those less knowledgeable about schizophrenia.

Preventive cardiology: what lies ahead?

Despite increased knowledge of the leading causes of cardiovascular diseases, we continue to observe rather than to control the rise and fall of their incidence. Research needs to be more oriented toward current uncertainties of policy: Is a high-fat diet acceptable so long as its polyunsaturated to saturated fat ratio is high? What are the long-term adverse effects of the powerful new cholesterol-lowering drugs? Should people eat more polyunsaturates? Can new understanding of clotting factors help to prevent heart attacks? How can we lower the average blood pressure of the population as a whole? How do maternal and child health influence the next generation's cardiovascular health? The new research to answer such questions requires that epidemiologists abandon the "black box" approach (which ignores mechanisms); instead, basic scientists need to explain the actions of environmental agents. A new style of preventive clinical practice is emerging, but its future success depends on changes in the medical care system (involving structure, rewards, and staffing), changes in medical education, and on the willingness of physicians to negotiate shared responsibility with their patients. Physicians can identify and help high-risk individuals; but because the incidence of heart disease depends on how people live, it follows that progress in prevention ultimately depends on social, economic, and political decisions. By successful communication of knowledge and impartial advice, physicians can assist in those decisions.

INTERSALT study findings. Public health and medical care implications

INTERSALT found a significant association between 24-hour urine sodium excretion and systolic blood pressure in individuals. There was also a significant association between sodium and slope (increase) of blood pressure with age across population samples. The weight of evidence from animal-experimental, clinical, intervention, and epidemiological data favors a causal relation. INTERSALT data from 52 centers in 32 countries permit an estimate of effect on average population blood pressure of lower sodium intake. Based on the sodium-blood pressure association in individuals, it was estimated that a habitual population sodium intake that was lower by 100 mmol/day (e.g., 70 vs. 170 mmol/day) would correspond to an average population systolic pressure that was lower by at least 2.2 mm Hg. This size difference in systolic blood pressure in major US and UK population studies is associated with 4% lower risk of coronary death and 6% lower risk of stroke death in middle age. If habitual diet is both lower in sodium and higher in potassium with lower alcohol intake and less obesity, INTERSALT data estimate average population systolic pressure would be lower by 5 mm Hg. This was calculated to correspond to a 9% lower risk of coronary death and a 14% lower risk of stroke death. INTERSALT cross-population data also suggest that, with a 100 mmol/day lower sodium intake over the life span, the average increase in population systolic pressure from age 25 to 55 years would be less by 9 mm Hg, corresponding at age 55 to a 16% lower risk of subsequent coronary death and 23% lower risk of stroke death.(ABSTRACT TRUNCATED AT 250 WORDS)

Restriction fragment length polymorphism of human mitochondrial DNA in a sample population from Apulia (southern Italy)

Restriction fragment length polymorphism (RFLP) of human mitochondrial DNA was analysed in a sample of 87 subjects from Apulia (South Italy) by the restriction enzymes HpaI, BamHI, HaeII, MspI, AvaII, and HincII using total blood cell DNA probed by human mtDNA from placenta. Five BamHI morphs were observed, two of which are new (BamHI-4 and -5), as well as one new AvaII morph (AvaII-28). The association BamHI-4/AvaII-28 enables us to demonstrate for the first time two polymorphic BamHI sites present together in the same mtDNA molecule. In agreement with historical data the Apulian sample has been shown to be the most heterogeneous Italian population so far tested.

The INTERSALT study: background, methods and main results. INTERSALT Co-operative Research Group

The INTERSALT study used standardised methods to assess the relations of electrolyte intake and blood pressure, taking account of confounding variables, in samples of men and women aged 20-59 drawn from defined populations in 52 centres and 32 countries (10,079 individuals). Sodium excretion was significantly related to blood pressure in individuals. Corrected estimates (probably still too low) indicated, on multiple regression, that a difference of 100 mmol/day in average population sodium intake corresponded to 2.2 mmHg lower systolic pressure. Sodium excretion across centres, with median levels ranging from 0.2 to 242 mmol/24 hour, was related to slope of blood pressure with age, less consistently to median centre pressure. Estimates indicated that a 100 mmol/day lower sodium intake was associated with a 9 mmHg lower rise of systolic pressure between ages 25 and 55. Hypertension was virtually absent in four populations with very low sodium intake, and blood pressure in these samples was not higher at older ages. Potassium intake of individuals was negatively and significantly associated with blood pressure independently of other variables; body mass index and high alcohol intake were strongly positively and independently associated with blood pressure in individuals.

Salt and blood pressure: a community trial

The effect of a health education programme on salt reduction and blood pressure was studied in two matched rural communities in Portugal, each of about 800 adult inhabitants. Initial salt intake was high (about 360 mmol/person/day) and 30% of persons were hypertensive (DBP 95 mmHg or above). In the intervention community average blood pressure fell by 3.6/5.0 mmHg at one year and 5.0/5.1 mmHg at two years, due to a general distribution shift. In the control community diastolic pressures remained stable and systolic pressures rose. The difference in trends between the two communities was highly significant. There were also significant correlations within individuals in the intervention community between fall in blood pressure and fall in urinary sodium/creatinine ratio. At least in this high-intake population a fall in salt consumption seems to have caused an important fall in average blood pressure.

Epidemiology of acute asthma: IgE antibodies to common inhalant allergens as a risk factor for emergency room visits

In recent years the morbidity and mortality of asthma has increased, although the etiology is still poorly understood. Most patients with asthma suffer acute attacks that are commonly treated in hospital emergency rooms (ER). In the present study, asthma in adults was studied with acute attacks as a marker for the disease; 102 patients first observed at a university hospital ER with acute airway obstruction were compared to 118 patients observed at the same ER with any diagnosis other than shortness of breath to evaluate allergy as a risk factor for asthma in adults. Sera were assayed for IgE antibody (Ab) to dust mites, cockroach, cat dander, and grass and ragweed pollen. The results demonstrate that in adults younger than 50 years of age, the prevalence of IgE Abs was fourfold greater among subjects with asthma than among control subjects (46/67 versus 12/81; odds ratio, 10.1; 95% confidence interval, 4.9 to 20.7). The population attributable risk for the presence of IgE Ab to one of the five allergens was greater than 50%. Among individuals older than 50 years of age, the prevalence of serum IgE Abs was not significantly increased among patients with acute airway obstruction. In the whole group, the prevalence of IgE Abs to different allergens demonstrated significant seasonal and socioeconomic differences, suggesting that the associated risk is related to exposure to those allergens. The results establish that, with acute attacks of asthma as a marker for adult asthma, the presence of serum IgE Abs to common inhalant allergens is a major risk factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Trichophyton asthma: sensitisation of bronchi and upper airways to dermatophyte antigen

12 adult patients with perennial asthma and chronic skin infection were found to have immediate hypersensitivity to Trichophyton spp. 10 patients were tested by bronchial provocation and gave immediate bronchial reactions to an extract of T tonsurans. Double-blind, placebo-controlled nasal challenge of 8 patients demonstrated that the upper airways of these patients were also sensitive to this dermatophyte antigen. In addition to perennial asthma most of the patients had persistent eosinophilia and chronic rhinosinusitis. The results suggest that absorption of fungal antigen can give rise to IgE antibody production, sensitisation of the airways, and symptomatic asthma and rhinosinusitis. Several patients had many of the features of late onset or "intrinsic" asthma.

Mitochondrial DNA polymorphism in Calabria (southern Italy)

Restriction Fragment Length Polymorphism (RFLP) of mitochondrial DNA (mtDNA) has been investigated in a sample from Calabria (Southern Italy). Seven restriction endonucleases (HpaI, BamHI, HaeII, MspI, AvaII, HincII and PstI) have been employed on 60 mtDNAs from placentas. Two new morphs have been identified (PstI-3Cal and AvaII-24Cal) and the respective polymorphic sites have been located by double digestion. Two new types (74 and 75) have also been identified and their possible origin from other known mtDNA types has been suggested.

Breathlessness, chronic bronchitis and reduced pulmonary function as predictors of cardiovascular disease mortality among men in England, Scotland and the United States

Relationships between cardiovascular disease (CVD) mortality and breathlessness, a definition of chronic bronchitis, and pulmonary function are investigated among men in two employed populations (17,717 London civil servants and 4904 Scottish workers) and in two communities (844 men in Tecumseh, Michigan and 6859 men in Renfrew and Paisley Burghs, Scotland). Men are aged 40-64 years at entry in all studies except Renfrew-Paisley, where they are aged 45-64 years. Length of follow-up ranges from 6 to 16 years. Age and smoking habits were controlled for in all analyses. Chronic phlegm production is not significantly associated with CVD mortality, and 'chronic bronchitis' is significantly associated with mortality only in the employed populations. Low FEV1 is significantly associated with CVD mortality only in the Whitehall study; however, the rate ratios are above one in all studies. Breathlessness is significantly associated with CVD mortality in all studies. These associations between CVD mortality and 'chronic bronchitis', low FEV1, and breathlessness persist after also controlling for employment grade, systolic blood pressure, antihypertensive medication, ECG changes, plasma cholesterol level, body mass index and diabetes. Only the associations between breathlessness and mortality persist after further controlling for low FEV1 and myocardial ischaemia. The rate ratios between breathlessness and mortality are about two for all studies. It is concluded that in these populations, breathlessness is an independent and major predictor of CVD mortality.

The INTERSALT study: main results, conclusions and some implications

INTERSALT is an epidemiological study of electrolyte excretion and blood pressure in 10,079 men and women from 52 centres and 32 countries. The data were collected according to strict protocol with extensive quality control, and were analysed both in individuals and across centres. In the individual analysis, with adjustment for confounding variables, significant positive associations were observed between blood pressure and twenty-four hour sodium excretion, body mass index and alcohol intake, and significant negative associations between blood pressure and potassium excretion. For a number of reasons, it is likely that the size of these relationships was underestimated. Across centres, linear slope of blood pressure with age was positively related to median sodium excretion. These observations imply that a policy combining changes in sodium and potassium intake with reductions in obesity and alcohol consumption could bring important public health benefits.

Temporal hyperacuity in single neurons of electric fish

Behavioural studies have revealed that animals can resolve temporal disparities in the microsecond range. This resolution is far superior to that of individual receptors, and it must therefore be achieved through central neuronal mechanisms. It is unclear, however, whether such sensitivity ever emerges at the level of single neurons, or whether it is apparent only at the behavioural level through the collective action of many less-sensitive neurons. We have found that single neurons in the pre-pacemaker nucleus of a weakly electric fish are sensitive to temporal disparities as small as 1 microsecond, the highest temporal sensitivity ever observed at the single-neuron level. The remarkable temporal resolution of these pre-pacemaker neurons results from a high degree of spatial convergence of afferent inputs. These neurons represent the final elements of a sensory hierarchy and directly control the jamming avoidance response by which these fish regulate the frequency of their electric organ discharges.

Nasal and hand carriage of Streptococcus pneumoniae in children and mothers in the Tari Basin of Papua New Guinea

Nasal and hand carriage of Streptococcus pneumoniae was looked at in 55 families. Overall nasal carriage was 61% (83% in children and 33% in mothers). Hand carriage was 14%. Just over half of the mothers who carried pneumococcus were concordant with their infants.

Correlation of IgA2 serum levels in parent-offspring pairs

IgA2 serum levels were measured by ELISA in 120 healthy subjects from 40 nuclear families (both parents and one offspring). No sex-associated difference was observed. Moreover, the IgA2 serum levels proved to be significantly correlated in parent-offspring pairs (r = 0.55; P less than 0.001), while there was no significant correlation in mother-father pairs of the same family. The data suggest that the serum level of the IgA2 subclass is genetically controlled.

Mortality of employees of the Atomic Weapons Establishment, 1951-82

A total of 22,552 workers employed by the Atomic Weapons Establishment between 1951 and 1982 were followed up for an average of 18.6 years. Of the 3115 who died, 865 (28%) died of cancer. Mortality was 23% lower than the national average for all causes of death and 18% lower for cancer. These low rates were consistent with the findings in other workforces in the nuclear industry and reflect, at least in part, the selection of healthy people to work in the industry and the disproportionate recruitment of people from the higher social classes. At some time during their employment 9389 (42%) of the workers were monitored for exposure to radiation, the average cumulative whole body exposure to external radiation being 7.8 mSv. Their mortality was generally similar to that of other employees, even when exposures were lagged by 10 years. The rate ratio after a 10 year lag in workers with a radiation record compared with other workers was 1.01 (95% confidence interval 0.92 to 1.10) for all causes of death and 1.06 (0.89 to 1.27) for all malignant neoplasms. The only significant differences were for prostatic cancer (rate ratio 2.23; 95% confidence interval 1.13 to 4.40) and for cancers of ill defined and secondary sites (rate ratio 2.37; 1.23 to 4.56). Cancers of lymphatic and haemopoietic tissues were notable for their low occurrence in the study population, with only four deaths from leukaemia and two from multiple myeloma in workers with a radiation record, 9.16 and 3.55 deaths respectively being expected on the basis of national rates. Among workers who had a radiation record 3742 (40%) were also monitored for possible internal exposure to plutonium, 3044 (32%) to uranium, 1562 (17%) to tritium, 638 (7%) to polonium, and 281 (3%) to actinium. In these workers mortality from malignant neoplasms as a whole was not increased, but after a 10 year lag death rates from prostatic and renal cancers were generally more than twice the national average, these excesses arising in a small group of workers monitored for exposure to multiple radionuclides. Though mortality from lung cancer in workers monitored for exposure to plutonium was below the national average, it was some two thirds higher than in other radiation workers, the excess being of borderline statistical significance. Mortality from malignant neoplasms as a whole showed a weak and non-significant increasing trend with increasing level of cumulative whole body exposure to external radiation. When the exposures were lagged by 10 years the trend became stronger and significant, the estimated increase in relative risk per 10 mSv being 7.6% (95% confidence interval 0.4% to 15.3%). This trend was confined almost entirely to workers who were also monitored for exposure to radionuclides (p<0.001), the main contributions coming from lung cancer and prostatic cancer. Exposures of the lung and prostate from internal sources of radiation were not quantified, except for the contribution from tritium. It was therefore not possible to assess the extent to which the associations were due to internally deposited radionuclides rather than external exposure. The finding for prostatic cancer taken in conjunction with the results of other studies suggest a specific occupational hazard in a small group of workers in the nuclear industry who had comparatively high exposures to external radiation and who were also monitored for internal exposure to multiple radionuclides. Research is needed to discover whether any of the radionuclides and other substances concerned are concentrated in the prostate. The occurrence of lung cancer in this workforce requires further investigation taking into account smoking habits and tissue doses from inhaled radionuclides.