Immunity to hepatitis B in two birth cohorts given plasma-derived or yeast-derived vaccine.

AIM: To determine the antibody response to either yeast-derived or low-dose, plasma-derived hepatitis B vaccine, in two cohorts of infants monitored by an immunisation coordinator and immunised by general practitioners. METHODS: Infants born to two cohorts of non-carrier mothers in Northland were followed up, the first receiving a low-dose, plasma-derived vaccine, the second a yeast-derived vaccine. An immunisation coordinator enrolled the mothers into the programme during pregnancy, promoted full immunisation against hepatitis B and later obtained blood samples from their babies. In each cohort, four subsamples of babies, randomly assigned, were bled for estimation of antibody levels to hepatitis B at ages 18, 30, 42 and 54 months (1 1/2, 2 1/2, 3 1/2, 4 1/2 years). No infant was bled more than once. RESULTS: In both cohorts, antibody levels declined significantly with age. By age 4 1/2 years, 5.1% of children (95% confidence interval (CI): 3.5-7.1) immunised with yeast-derived vaccine were estimated to have antibody levels to hepatitis B below the acceptable level for protection of 10 IU/L. The proportion for those immunised with plasma-derived vaccine was 14.3% (95% CI: 7.4-24.1). CONCLUSIONS: Children receiving yeast-derived vaccine do not require a second booster dose at school entry, although this might be considered at age 11. There are grounds to suggest that those who received low-dose, plasma-derived vaccine (prior to 1990) should be offered a booster before age 11.

Acidic isoforms of chorionic gonadotrophin in European and Samoan women are associated with hyperemesis gravidarum and may be thyrotrophic.

OBJECTIVE: There is conflicting evidence concerning the role of human chorionic gonadotrophin (hCG) in the aetiology of hyperemesis gravidarum (HG); particular isoforms of hCG may be the critical factor. Ethnic differences in HG prevalence and putative thyrotrophic effects of hCG may also relate to differences in hCG isoform profiles. To address these issues we examined the relationship of hCG isoforms to HG and thyroid function tests in two groups of women from ethnic backgrounds with significantly different HG prevalence rates. PATIENTS AND DESIGN: We enrolled 10 European and 10 Samoan women with HG and an equally sized non-hyperemetic, gestational stage matched control group. MEASUREMENTS: We administered a questionnaire, generated serum hCG charge-isoform profiles by chromatofocusing and measured the serum concentrations of total hCG, oestradiol (E2), thyrotrophin (TSH) and free thyroxine (FT4). RESULTS: The mean serum total hCG levels were highest in the Samoan hyperemetics (176,268 IU/l), and overall higher in hyperemetics compared with controls (159,770 IU/l vs. 86,420 IU/l, P < 0.001). When compared with controls, hyperemetics displayed increased hCG concentrations in the more acidic half (pH < 4) of the chromatofocusing pH range (89,843 IU/l vs. 41,146 IU/l, P < 0.003). Serum E2 levels did not differ between the four groups, but correlated with the hCG concentration between pH 5.2 and 4.01. Mean serum TSH levels were significantly lower in hyperemetics than in controls (0.33 mIU/l vs. 1.19 mIU/l, P < 0.001) and correlated with the hCG concentration between pH 4.6 and 2.8, while serum FT4 correlated with the hCG concentration below pH 4.0. CONCLUSIONS: Acidic isoforms of hCG may play a role in the aetiology of HG and gestational thyrotoxicosis. Minor ethnic differences in hCG isoform profiles were observed, but the relationship of acidic hCG isoforms to HG and serum thyroid hormone levels was largely independent of the patients' ethnicity. The mechanisms by which acidic isoforms might provoke nausea remain uncertain, but do not seem to involve E2, while the longer half-life of acidic hCG isoforms may result in increased in vivo TSH receptor cross-talk with resultant thyrotrophic effects.

The Nelson Prescribing Project. A programmed intervention in general practice in New Zealand.

We have defined the effect and acceptability of a locally developed general practice programme for the modification of prescribing. This voluntary programme consisted of prescription analysis and feedback, followed by visits from a pharmacist, a therapeutic bulletin on benzodiazepine prescribing, and use of a locally compiled preferred medicines list. A 3-month prescription sample from 26 general practitioners (GPs) fulfilling a stable practice definition was used to compare prescribing pre-project and mid-project. For 20 out of 26 GPs, prescribing of medicines on the preferred medicines list had increased significantly 8 months after the intervention programme had been introduced. Total prescription numbers and total medicines expenditure decreased by 8.3 and 4.9%, respectively, from 1988 to 1989. The decrease in benzodiazepine prescribing was marked (mean -22.2%, range -50.3 to +4%). The cooperative multimodel approach was highly successful in modifying prescribing in general practice.

Impact of a promotion program for hepatitis B immunisation.

This study compared levels of hepatitis B immunisation in a group of 524 infants in Northland, New Zealand, with levels in the remainder of the country. The Northland sample had specific encouragement from an immunisation coordinator and had been followed from birth. Levels throughout the rest of the country were estimated from four samples totalling 317 infants whose parents were interviewed when the child was at least two years old. The cross-sectional nationwide sample had fewer children 'fully immunised' by two years of age (minimum estimate 61.8 per cent, maximum estimate 69.7 per cent) than the cohort of children (not lost to follow-up) who were encouraged to have the immunisations in Northland (77.5 per cent) (Z = 4.73, P < 0.001 for comparison with the minimum nationwide estimate; Z = 2.45, P = 0.014 for comparison with the maximum estimate). Of the Northland cohort, 13.5 per cent were lost to follow-up before the scheduled completion of the hepatitis B vaccinations. Assuming that every child lost to follow-up was not fully immunised, the efforts of the immunisation promotion program operated by a nurse coordinator increased the percentage of children fully immunised by between about 7.8 per cent and 15.7 per cent. A promotion program for hepatitis B immunisation, operated by an immunisation coordinator, is an effective tool for increasing immunisation coverage.

Trends in amenable mortality in New Zealand 1968-1987.

Trends in amenable mortality rates for Maori and non-Maori New Zealanders were analysed and compared using regression models. The contribution of medical services to the decline in mortality rates was estimated. Mortality from causes amenable to medical intervention declined at a greater rate than non-amenable mortality for both groups. The proportion of the decline in mortality attributable to improvement in the impact of medical services was greater for non-Maori than for Maori, especially for females. Maori to non-Maori mortality ratios were greater for amenable than for non-amenable causes, indicating a systematic differential between the two groups in the impact of medical services. There was only a small improvement over the 20 years in the excess of amenable mortality suffered by Maori. The results have implications for the provision of medical services to Maori people.

Platelet 3H-imipramine binding during recovery from depression.

Decreased binding of tritiated imipramine to platelets has been considered to be a potential biological marker of depression. However, it has been unclear how binding values alter during treatment and recovery. This study investigated imipramine binding parameters and depressive symptoms in 25 patients suffering from major depression at entry to the study and 1, 3 and 6 months later. Although the initial Bmax values were significantly lower in the depressed patients than in healthy subjects, it was not possible to establish a clear relationship between recovery from depression and Bmax. The power of this study to detect an effect of at least 10% of the variance in Bmax due to factors related to recovery from depression was 0.78.

Occupational risk of hepatitis B for police and customs personnel.

A cross-sectional study was undertaken in 1987 to establish whether New Zealand police and customs officers are at excess risk of hepatitis B virus infection as a consequence of occupational exposure to human blood and penetrating injury. The study population comprised all full-time police (n = 5,193) and customs officers (n = 1,026) excluding only a small number on special duty who had already been immunized. The control group comprised the civilians employed by both organizations (n = 964). The prevalence of hepatitis B markers in the control group, when standardized for age, sex, and ethnic distribution, was 13.4%, which agrees well with New Zealand blood donor figures. The prevalence ratios for police officers and customs officers compared with the civilians (adjusted for age, sex, and ethnic distributions) were 0.82 (95% confidence interval (CI) 0.63-1.06) and 0.49 (95% CI 0.34-0.70), respectively. Multivariate analysis was used to further explore the differences in marker prevalence among the three groups, but failed to demonstrate any significant association between occupational variables and marker prevalence. There was an association between time spent living in high-risk areas of the country and marker prevalence. The authors conclude that the question as to whether police personnel should be immunized begs the wider issue of whether or not the whole New Zealand population should be so protected.

Viral and bacterial infection in childhood: the value of C reactive protein.

In 199 children with acute infections admitted to an acute general paediatric ward, the serum C reactive protein (CRP) level, using a simple latex agglutination kit, was compared with standard haematological parameters in distinguishing children with viral and bacterial infections. CRP levels proved superior to any haematological parameters singly or in combination in distinguishing these groups. A CRP level of 1:4 identified all but 13% of children with viral infections and excluded all but 15% of children with bacterial infections. The sensitivity of the test was 87%, the specificity 85%. The positive and negative predictive values were 95% and 74% respectively. Combined haematology, using total white cell count, total neutrophil count and percentage neutrophils, misclassified 26% of patients. CRP estimation could potentially help reduce unnecessary antibiotic prescription and shorten hospitalisation in febrile children. Its use in a general practice setting deserves further study.

Clinical assessment of ankylosing spondylitis: a study of observer variation in spinal measurements.

Twenty-two measurements repeated non-sequentially on each of 10 patients by five observers were undertaken to determine their reliability for routine clinical use. Measurements without significant inter-observer variation or with a coefficient of reliability greater than 0.70 were cervical rotation, cervical lateral flexion, tragus to wall distance, fingertip to floor distance on sagittal and lateral flexion, C7 to iliac crest line distraction and modified Schober index. It is concluded that many of the currently used measurements are either statistically unreliable or clinically unhelpful in mild or moderate ankylosing spondylitis. The most clinically useful were cervical rotation using a protractor, cervical lateral flexion using a goniometer, thoracolumbar flexion as the C7 to iliac crest line distraction, thoracolumbar lateral flexion as the fingertip to floor distance and the modified Schober index.

Platelet tritiated imipramine binding in psychiatric patients: relationship to symptoms and severity of depression.

The clinical and research significance of reduced imipramine binding has remained unclear despite considerable investigation. This study used an assay of demonstrated reliability to investigate the clinical correlates of imipramine binding to platelets in 63 depressed and 33 nondepressed psychiatric patients and 40 healthy control subjects. Both patient groups had Bmax values significantly lower than those of the healthy controls. Unequivocal associations between binding parameters and individual symptoms or groups of symptoms were not established, but a negative correlation between Kd and the number of adverse life events experienced in the preceding 6 months was apparent. These findings provide no support for the view that reduced binding is a trait marker for susceptibility to depression and cast doubt on its specificity as a state marker for the syndrome of depression.

Type 2 (non-insulin-dependent) diabetes mellitus, migration and westernisation: the Tokelau Island Migrant Study.

The migration of Tokelauans from a traditional atoll in the Pacific to urban New Zealand is associated with an increased prevalence and incidence of Type 2 (non-insulin-dependent) diabetes mellitus over the period 1968-1982. During the same period, a lesser but definite increase is seen among non-migrants in Tokelau. The age standardised prevalence rates rose from 7.5 and 11.7 to 10.8 and 19.9 per 100 respectively in the male and female migrants compared with an increase from 3.0 and 8.7 to 7.0 and 14.3 per 100 in the non-migrant males and females respectively. The incidence of diabetes is shown to be consistently higher in the migrants compared to the non-migrants giving relative risks of 1.5 in males and 1.9 in females. The factors most likely contributing to this difference, are changes to a higher calorie, high protein diet, higher alcohol consumption, a greater weight gain and altered levels of physical activity in the migrants. A number of populations in the Pacific have been shown to have a low rate of diabetes in their traditional setting, but may have a genetic predisposition for diabetes which responds to factors in the urban industrialised environment and life-style. The social and economic changes taking place in Tokelau are also clearly increasing the risk of diabetes. To reverse these trends and prevent the development of complications of Type 2 diabetes, it will be important to institute preventive programmes and to follow up the population in both environments for long-term outcomes, including mortality.

Blood pressure patterns and migration: a 14-year cohort study of adult Tokelauans.

The longitudinal relation between blood pressure changes and migration experience has been studied in a cohort of 654 adult Tokelauans through three survey periods between 1968 and 1982. Migration from a subsistence life-style on a Pacific atoll to an urbanized Western life-style in New Zealand is associated with increases in body mass in both men and women. Both the systolic and diastolic blood pressures of migrant men are significantly higher than would be expected in this cohort on the basis of age when compared with the nonmigrants. This is consistent with a rise around the time of migration to a level which is then maintained, with the diastolic pressures taking longer than the systolic pressures to respond to the migration stimuli. Most of this rise in blood pressure may be attributed to weight gain, but a significant part of the diastolic pressure excess remains unexplained. This pattern is not exhibited by the women, which may be a reflection of the sex roles in this Polynesian society. These findings indicate a need for new immigrants to be encouraged not to gain weight when confronted with new dietary choices.

Prevalence of hepatitis B among school dental nurses.

A survey of hepatitis B serological markers and associated risk factors was carried out among school dental nurses in 1985. A postal questionnaire provided information on demography, years worked and residential history from birth to 10 years of age. A blood sample was provided by 1015 subjects (95% response). All sera were tested for HBsAg, anti-HBs and anti-HBc, and HBsAg positive sera for HBeAg and anti-HBe. Twenty-three percent of subjects were both anti-HBs and anti-HBc positive, 2% were anti-HBs positive and 3% anti-HBc positive only. Less than 1% were HBsAg positive. Prevalence varied with geographic area--40% in the north and east of the North Island, 25% in the south and west of the North Island and 5% in the South Island. There was a linear increase in marker prevalence with age group in subjects under 45 years. Only in the north and east of the North Island was there a relationship (inverse) between the proportion of Europeans treated and marker prevalence. Childhood residence had little effect on prevalence (p less than 0.001). The results suggest that infection occurred during adult life, whether as a result of occupation or area of residence cannot be determined without a control group.

Migration and gout: the Tokelau Island migrant study.

The prevalence and 14 year incidence of clinical gout and its precursors were investigated in the Polynesian population of Tokelauans living in the Pacific basin, non-migrant Tokelauans living in their isolated atoll homeland being compared with migrant Tokelauans living in urban New Zealand. The age standardised prevalence of gout in Tokelauan men in New Zealand was higher than that in non-migrant Tokelauan men, being 21.0 and 19.5/1000 subjects at the beginning of the study and 51.0 and 14.6/1000 at the end of study, respectively. Migrant men in New Zealand aged under 55 had higher mean serum uric acid concentrations than non-migrant men of the same age. The prevalence of gout was low in women in both environments. The age standardised relative risk of developing gout between 1968 and 1982 was 9.0 times higher in the migrant men than in the non-migrant men. Age, serum uric acid concentration, serum cholesterol concentration, and self reported alcohol consumption at entry to the study were the best set of predictors of gout in men. Preventive strategies to change body mass, diet, and patterns of alcohol use need to be developed in this population.

Stability of total cholesterol, high-density-lipoprotein cholesterol, and triglycerides in frozen sera.

When human serum must be stored for extended periods before analysis, conditions must be such that samples give results comparable with those for "fresh" (unstored) samples. In a balanced experiment with statistically pre-determined sample size, we assessed, at three-weekly intervals for 18 weeks, the stability of total cholesterol, high-density-lipoprotein cholesterol, and triglycerides in human serum stored at -15 degrees C. No significant changes were observed.

Hypertension among urban and rural Tongans.

A cross-sectional study of urban and rural Tongans showed the prevalence of hypertension to be 8.4%. Hypertension occurred more often in urban men than in women. Systolic blood pressure (BP) showed a significant increase with age in all groups, except among rural men. Multivariant discriminant analysis identified the characteristics that were associated with a raised BP. The independent variables were selected for entry into the analysis on the basis of their power to separate BP categories, using Rao's V as the generalized measure of distance between groups. Age and body build (BMI or Fatsum) accounted for most differences between normotensive and hypertensive persons, especially in women. The fasting plasma glucose level was a significant discriminating characteristic for both men and women. The packed red cell volume was the most powerful single discriminating characteristic in men and the serum triglyceride level in women. The use of each characteristic to classify individuals by BP category may help clinicians to use cross-sectional data when deciding on the treatment of raised BP.

Longitudinal analysis of the relationship between blood pressure and migration: the Tokelau Island Migrant Study.

The Pacific atoll population of Tokelau has been followed since 1968 to assess the health consequences of migration to a western society. The blood pressure of a cohort of 532 adults who were still living in Tokelau in 1976 (nonmigrants) are compared with those of a cohort of 280 adults who had migrated to New Zealand (migrants). Significant differences between migrants and nonmigrants were detected in the rates of change of both systolic and diastolic pressures in men, and in the rates of change of diastolic pressures in women. The age-, body mass, and blood pressure-corrected rates of change were greater in migrants than in nonmigrants, and greater in men than in women. Blood pressures tend to rise 1 mmHg/year faster among male migrants than among male nonmigrants, and about 0.4 mmHg/year faster among female migrants than among female nonmigrants. These findings have clear implications for the health of migrants.

Are low cholesterol values associated with excess mortality?

The relation between cholesterol concentration and mortality was studied prospectively over 17 years in 630 New Zealand Maoris aged 25-74. The dead or alive state of each person was determined in 1981. The causes of death were divided into three categories: cancer, cardiovascular disease, and "other." Using univariate and both linear and non-linear multivariate methods of analysis for survivorship data, significant inverse relations with serum cholesterol were found for total mortality in women, for mortality from cancer in men and women, and for other causes of mortality in both men and women. The inverse and non-linear association with total mortality in women remained significant when deaths in the first five years of follow up were excluded. This suggests that the association was not explained by undetected illness causing low cholesterol concentrations at the time of initial examination.

The health status of fourth form students in Northland.

A random sample of fourth form students throughout Northland was studied. Uncorrected visual defects were found in 4.5% and significant hearing loss in 9.1%. Appreciable numbers were overweight; 6.2% of boys and 22.5% of girls exceeded the desirable bulk index range. Levels of total cholesterol appear decreased compared to earlier New Zealand studies and were significantly lower than the Wairoa College survey levels. There was a strong correlation between total cholesterol and low density lipoprotein cholesterol. High density lipoprotein cholesterol was significantly higher in non-Maori than in Maori girls. Overall systolic blood pressure for boys at 114.3 mmHg (15.2 kPa) was significantly higher than for girls at 109.5 mm Hg (14.56 kPa). One-third of boys exceeded the adult uric acid reference range; a significantly higher proportion than for girls. Fifteen point one percent of boys and 23.5% of girls reported smoking seven or more cigarettes per week; 19.1% of boys and 9% of girls reported taking regular amounts of alcohol at least every weekend.

Elevation of systolic and diastolic blood pressure associated with migration: the Tokelau island migrant study.

Cross-sectional univariate and multivariate analyses estimated differences between the blood pressure of adult Tokelauan migrants to New Zealand and non-migrants still living on three Polynesian atolls. Response rates were 97 and 99% in the two locations. Among males, the difference between migrants and non-migrants after adjustment for significant covariates was 7.2 mmHg systolic pressure (p less than 0.001) and 8.1 mmHg diastolic pressure (p less than 0.001). Among females, adjusted systolic pressure was not significantly higher in migrants compared to non-migrants (1.8 mmHg, p = 0.065) and diastolic pressure was only 3.0 mmHg higher (p less than 0.001). Body mass is significantly correlated with blood pressure in this study group; nonetheless, differences in body mass explain only a small proportion of the observed migrant/non-migrant differential in blood pressure. Estimates of blood pressure differences preceding migration are also reported. These indicate that blood pressure was neither consistently nor significantly higher among those who subsequently migrated. This report provides compelling evidence linking Westernization and the development of chronic disease.