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Biomedical subjects

R Scragg

Publications and source records attributed to R Scragg.

At least 19 recordsLinked to original sources

Potential for prevention of premature death and disease in New Zealand.

AIM: To assess the potential for preventing major causes of premature death, disease and injury in New Zealand. METHODS: Population attributable risks for major modifiable risk factors for important causes of death and disease in New Zealand were calculated using available national and international data on the relative risk of disease and the prevalence of risk factors in the relevant New Zealand population. Attainable changes in risk factor prevalences were used to model population attributable risks over the next five years. These estimates were then used to estimate potential reductions in absolute numbers of deaths from major diseases. RESULTS: High population attributable risks were found for several disease/risk factor combinations: smoking and lung cancer (81% in Maori), smoking and coronary heart disease (44% in Maori), smoking and sudden infant death syndrome (49% in Maori); raised serum cholesterol and coronary heart disease (58%); physical inactivity and coronary heart disease (35%), physical inactivity and diabetes (30%), physical inactivity and colorectal cancer (33%), physical inactivity and fractured neck of femur (65%); obesity and hypertension (66%), obesity and diabetes (46%); lack of fruits and vegetables and stomach cancer (46%), and colorectal cancer (34%). The estimated, readily attainable reduction in absolute numbers of annual deaths due to decrease in risk factor prevalence was greatest for smoking (457 deaths), followed by hypertension (326), physical inactivity (303) and raised serum cholesterol (142). CONCLUSION: There is significant scope for reducing mortality from major non-communicable diseases although for some diseases such as the cancers, there will be a time lag of many years before the full benefits are realised. Together, reducing the prevalence of smoking, hypertension, physical inactivity and raised serum cholesterol would result in 1228 fewer deaths per year.

Exercise

Hospitalization for pneumonia in children in Auckland, New Zealand.

OBJECTIVE: To describe the epidemiology of hospitalizations for pneumonia in children in Auckland, New Zealand. METHODS: A consecutive sample of children hospitalised with pneumonia at the Starship Childrens Hospital from 1 July 1993 to 30 June 1996. Subjects were Pacific Island, Maori, and European/other children aged 0-14 years resident in north, west and central Auckland who were hospitalized with pneumonia. Comparisons were made of the number of hospitalisations by year, ethnicity, age and season; and of the hospitalisation rates by year, ethnicity and age. RESULTS: There were 681 children who were hospitalized with pneumonia during 1993-94, 731 during 1994-95 and 630 during 1995-96. The average annual hospitalization rate was 5.0 per 1000 children aged 0-14 years (95% CI 4.8-5.2). The average annual hospitalisation rate for Pacific Island children was 14.0 per 1000 (95% CI 13.0-14.9), for Maori children 6.7 per 1000 (95% CI 6.0-7.4) and for European/other children was 2.7 per 1000 (95% CI 2.6-2.9). Fifty-three per cent of the hospitalised children were less than 2 years of age. A larger percentage of Pacific Island (61%) and Maori (60%) children were aged less than 2 years compared to European/other (42%) children (P < 0.001). There was marked seasonal variability in the number of hospitalizations, with peaks in hospitalizations corresponding to peaks in positive respiratory viral isolates. CONCLUSIONS: Pneumonia was a consistent cause of hospitalisation for a large number of Auckland children during this 3-year period. Hospitalisation rates and age distribution varied with ethnicity. Hospitalization rates were highest for Pacific Island. intermediate for Maori and lowest for European/other children. Based on these hospitalisation data, pneumonia is a significant cause of morbidity for children in Auckland, New Zealand.

Adolescent

Heavy caffeine intake in pregnancy and sudden infant death syndrome. New Zealand Cot Death Study Group.

AIMS: To examine the association between maternal caffeine consumption during pregnancy and the risk of sudden infant death syndrome (SIDS). METHODS: A nationwide case-control study surveying parents of 393 SIDS victims and parents of 1592 control infants. Caffeine consumption in each of the first and third trimesters was estimated by questionnaire. Heavy caffeine intake was defined as 400 mg/day or more (equivalent to four or more cups of coffee per day). RESULTS: Infants whose mothers had heavy caffeine consumption throughout their pregnancy had a significantly increased risk for SIDS (odds ratio 1.65; 95% confidence interval 1.15 to 2.35) after adjusting for likely confounding factors. CONCLUSION: Caffeine intake has been associated with fetal harm and now SIDS. Reducing heavy caffeine intake during pregnancy could be another way to lessen the risk of SIDS. This needs confirmation by others.

Caffeine

Sale of cigarettes to school children aged 14 and 15 years in New Zealand.

AIMS: To determine the sources of cigarettes and extent of illegal sales to 14 and 15 year old children, and to examine associated risk factors in order to more effectively reduce tobacco access to children. METHOD: Nationwide cross sectional survey of fourth form school children in New Zealand by means of an anonymous self administered questionnaire. RESULTS: Questionnaires from 14,097 fourteen and fifteen years olds were analysed, with over one third smokers. Twenty four percent of the whole group (3432) had bought cigarettes in the last year. Of smokers, 59.9% bought their own, with the great majority (68.9%) from dairies, particularly females. Ninety five percent said it was "easy" or "very easy" to buy cigarettes, and this was a major risk factor for this behaviour (relative risk (RR) = 2.01, 95% confidence interval (CI) 1.74, 2.32, RR = 2.54, CI 2.28, 2.83, respectively). Only 24.6% children had ever been refused cigarettes because of age and all points of sale were comparable in this respect. Heavy smokers and males were more likely to have been refused. While refusal was associated with a fourfold increase in the perception that it was difficult to buy cigarettes, there was only a minimal reduction in the risk of children buying their own cigarettes (RR = 0.95, CI 0.91, 1.00). CONCLUSION: We have shown that the illegal sale of cigarettes to children is unacceptably easy and accurately perceived as such by children who smoke. The active enforcement of existing or future legislation is essential, with prosecution of offending retailers, if we are to make any progress to reduce the high prevalence of smoking in New Zealand children.

Adolescent

A comparison of two pertussis epidemics in Auckland.

AIM: To determine if the addition of the 6 week dose of pertussis vaccine in 1984 was associated with any change in the hospitalisation rate for children with pertussis and the higher hospitalisation rates for Maori and Pacific Islander children with pertussis. METHODS DESIGN: Population based study of pertussis hospitalisations using a retrospective chart review of hospitalisation data for children during the 1991 epidemic, which was compared to previously published data from the 1982 epidemic. SETTING: Princess Mary and Middlemore hospitals, Auckland. SUBJECTS: Children aged 0-14 years resident in metropolitan Auckland and hospitalised in Auckland during 1982 or 1991 with pertussis. MEASUREMENTS: Hospitalisation rates were calculated as number of children with a discharge diagnosis of pertussis per 1000 children aged 0-14 years based on 1981 and 1991 census data. 1982 data were converted to person-years as published report was for an 8 month period. Hospitalisation rates were compared as a relative risk (RR) of hospitalisation in 1991 versus 1982. RESULTS: There were 84 cases during 8 months in 1982 and 66 cases in 1991. Rates of hospitalisation by ethnic group; in 1982 were 0.24 Other/European (OE), 1.98 Maori (M), 1.37 Pacific Islander (PI); and in 1991 were 0.22 OE, 0.51 M, 0.40 PI. Compared to 1982 the relative risk of hospitalisation in 1991 adjusted for ethnicity was 0.43 (CI 0.33, 0.58, p < 0.0001). Compared to 1982 there was a significant reduction in the hospitalisation rate in 1991 for M (RR = 0.26, CI 0.16, 0.43, p < 0.0001); and PI children (RR = 0.29, CI 0.16, 0.54, p < 0.0001); but not for OE children (RR = 0.91, 95% CI 0.57, 1.46, p = 0.70). CONCLUSIONS: There was a significant reduction in the rate of hospitalisation for pertussis in 1991 compared to 1982. This reduction in hospitalisation rate was due to a reduction in rates for Maori and Pacific Islander children.

Adolescent

Reproducibility and validity of a food frequency questionnaire in European and Polynesian New Zealanders.

The reproducibility and validity of a self-administered 142-item food-frequency questionnaire (FFQ) was assessed in a population comprising 124 European and 52 Polynesian (17 Maori and 35 Pacific Island) New Zealanders aged 40-65 years. Reproducibility correlation coefficients, determined by administration of the same questionnaire on two occasions 3 years apart, were higher in European than Maori and Pacific Island participants, ranging from 0.47 to 0.87 in Europeans (median 0.66) and from 0.41 to 0.79 in Maori and Pacific Island people (median 0.44). In general, there were no significant differences in mean nutrient intakes calculated from the two FFQs by Europeans or Maori and Pacific Island participants despite their cultural and language differences. When the FFQ was compared with a 3-day food diary in a subsample of 101 Europeans, 15 Maori and 22 Pacific Islanders, the validity was good for most nutrients, with overestimation of a few nutrients in each ethnic group. Correlation coefficients between the 3-day food diary and FFQ ranged from 0.41 to 0.81 in Europeans (median 0.48) and from 0.36 to 0.56 in Maori and Pacific Island people (median 0.55). Ratios of energy intake to resting metabolic rate suggested that Maori and Pacific Island people were more likely to underestimate their habitual energy intake by the 3-day diet diary method compared to Europeans, but that Europeans were more likely to underestimate total energy intake by the food frequency method and Pacific Island participants to overestimate it. Obese Europeans and Maori were more likely to under-report dietary intakes by the 3-day diary method. We conclude that our FFQ performed better in European than Maori and Pacific Island participants.

Adult

SIDS, illness, and acute medical care. New Zealand Cot Death Study Group.

One component of the Back to Sleep campaign to reduce the risk of sudden infant death syndrome (SIDS) is the recommendation that parents seek medical attention if their infant is unwell. The aim of this study was to investigate of SIDS could in part be explained by sick infants not getting appropriate medical care. Data on symptoms of illness and on acute medical contacts made for infants dying from SIDS (n = 390) within two weeks of their death were compared with those from a randomly selected group of control infants (n = 1592). SIDS cases had more severe illness than controls (odds ratio (OR) = 3.43; 95% confidence interval (CI) = 1.69 to 5.38), and were more likely to have seen a general practitioner (OR = 1.37; 95% CI = 1.09 to 1.73) or attended hospital (OR = 3.43, 95% CI = 1.09 to 1.73). Only 1.3% of all SIDS cases had symptoms suggesting severe illness and had not seen a general practitioner. A lack of medical contacts in the two weeks before death does not contribute to the risk of SIDS.

Acute Disease

Why is sudden infant death syndrome more common at weekends? The New Zealand National Cot Death Study Group.

OBJECTIVES: To determine whether the prevalence of known risk factors and the magnitude of their association with sudden infant death syndrome (SIDS) differed between weekends and weekdays. METHOD: A large nationwide case-control study, comparing interview data for 393 cases with 1591 controls. RESULTS: Sudden infant death syndrome occurred more often at weekends, more deaths occurring on Sunday than on any other day of the week. Significant interaction effects were found between weekends and sharing a room with an adult and the parents going to a party. After adjustment for confounders, room sharing was less protective at the weekends (odds ratio (OR) = 0.66, 95% confidence interval (CI) 0.43 to 1.03) than it was on weekdays (OR = 0.41, 95% CI 0.30 to 0.57) using not room sharing and weekdays as the reference group. Although the likelihood of SIDS after a party was higher at weekends (OR = 2.47, 95% CI 1.11 to 5.47) than on weekdays (OR = 0.55, 95% CI 0.21 to 1.37), few cases were reported. Being Maori (OR = 3.35, 95% CI 1.75 to 6.43) or the child of an unmarried mother (OR = 3.91, 95% CI 2.20 to 6.92) were risk factors for SIDS occurring on Sundays. CONCLUSIONS: The increase in SIDS at weekends may be explained in part by the lesser protective effect of sharing a bedroom with an adult at that time. It may also be related to social activities that occur at weekends.

Case-Control Studies

Body mass index and cardiovascular risk factors in Pacific Island Polynesians and Europeans in New Zealand.

OBJECTIVES: To examine relationships between body mass index (BMI) and cardiovascular risk factors in 279 Europeans and 231 Polynesian Pacific Islanders in New Zealand. METHODS: Participants were recruited from Seventh-Day Adventist church meetings or camps, and were surveyed by self-administered questionnaire. Blood pressure, weight and height were measured. Fasting blood samples were analysed for lipids, glucose and fructosamine. RESULTS: Age-adjusted BMI was higher in Pacific Islanders than in Europeans: 32.8(0.3) versus 25.6(0.3); means(SE); p = 0.0001). In Europeans, BMI was positively associated with systolic and diastolic blood pressures, triglycerides, total cholesterol, LDL cholesterol and fasting blood glucose, and negatively associated with HDL cholesterol. In Pacific Islanders, BMI was associated only with systolic and diastolic blood pressures, and with HDL cholesterol. These associations were stronger in Europeans than in Pacific Islanders. CONCLUSIONS: In this group of Pacific Islanders, the association between BMI and cardiovascular risk factors was weaker than in Europeans. This suggests that either BMI is a poor measure of adiposity in Pacific Islanders, or that adiposity may be less strongly linked to cardiovascular disease in Pacific Islanders.

Adult

Prevalence of Helicobacter pylori infection in different ethnic groups in New Zealand children and adults.

BACKGROUND: Helicobacter pylori infection is a major risk factor for peptic ulcer disease and gastric cancer. A study of patients with dyspepsia attending for gastroscopy showed significant differences in H. pylori seropositivity between ethnic groups. AIMS: To determine the prevalence of H. pylori in children and adults in the community in different ethnic groups and to identify risk factors for infection. METHODS: Serum samples (324) were randomly selected from a cross-sectional survey of 11-12 year old school children with a high proportion of Maori and Pacific Island groups. Serum samples (579) were randomly selected from a cross-sectional workforce survey of 5677 participants aged 40-64 years. Serum samples were tested for H.pylori IgG. RESULTS: The percentage seropositivity in 11-12 year old children was European 7%, Maori/part Maori 21%, all Pacific Island groups 48% and for the workforce survey 35.8%, 57.4% and 73.2% respectively. Compared with Europeans the increased relative risk of seropositivity for H.pylori in Maori and Pacific Island participants was significant after adjusting for age and socio-economic status (1.43 [1.13, 1.80] and 1.76 [1.43, 2.18]) respectively. The relative risk of H.pylori infection significantly increased with age, lower socio-economic status and lower household income, but was not significantly associated with gender, alcohol or cigarette use. CONCLUSIONS: The high seroprevalence of H.pylori in Maori and Pacific Island groups is consistent with the differences in incidence of gastric cancer. H.pylori continues to be a common infection in Maori and Pacific Island school children. Ethnicity appears to be a risk factor for H.pylori independent of socio-economic status.

Adult

Life events, social support and the risk of sudden infant death syndrome.

The effects of a lack of maternal social support and stressful life events on the risk of Sudden Infant Death Syndrome (SIDS) were examined by case-control design: 390 cases and 1592 control infants. A seven item index of mother's social support was used. A possible 21 life events experienced by each family were summed and then put into one of three categories: 0-2, 3-5, and 6 or more life events. Similar levels of maternal social support were found for both groups. SIDS families experienced significantly more stressful life events than control families, but once social factors had been taken into account this association was lost.

Analysis of Variance

Growth and the sudden infant death syndrome.

OBJECTIVE: To compare the growth curves based on measurements of body weight for male and female infants dying of sudden infant death syndrome (SIDS) with those of male and female controls. METHODS: The data were drawn from a large case control study of SIDS carried out in New Zealand between 1987 and 1990. RESULTS: The mean birthweight for the cases was 3049 g and for the controls 3526 g. The mean growth curves for the male and female controls were close to the 50th centile of growth charts used in New Zealand. The growth curve for the male cases diverged from that of the controls, being closer to the 25th percentile. The differences between the female cases and controls were less pronounced. The differences in weekly weight increments derived from the curves for the cases and controls for nine 4-week periods were not statistically significant after taking into account race, manner of feeding and maternal smoking for any 4-week period. CONCLUSIONS: SIDS cases were lighter at birth, but their growth velocity was normal postnatally.

Body Weight

Allergy and the risk of sudden infant death syndrome. The Members of the New Zealand Cot Death Study Group.

BACKGROUND AND OBJECTIVE: There are several sources that suggest that there is a link between allergy and sudden infant death syndrome. We endevavoured to look for evidence of an association between allergic disease and the risk of sudden infant death syndrome (SIDS). METHODS: A nationwide case-control study covering a region with 78% of all births in New Zealand during 1987-90. Interviews were completed with the parents of 393 (81.0% of total) infants who died from the sudden infant death syndrome (SIDS), and 1592 (88.4% of total) control families who were a representative sample of all hospital births in the study region. RESULTS: Eczema was reported in 13.9% control infants compared with only 8.0% of the SIDS infants, univariate odds ratio for this in terms of risk for SIDS was 0.56 (95% confidence interval 0.37, 0.84) for infants with eczema compared with those without. This lesser risk for SIDS was unchanged when adjusted for potential confounding factors. The risk of SIDS was not associated with reported cow's milk reactions or a family history of allergic symptoms once adjustments were made for possible confounding factors. CONCLUSION: Infants with skin disorders identified by their parents as eczema had a low risk for SIDS. Families can be reassured that atopy is not a risk factor for SIDS.

Asthma

A national survey of cigarette smoking in fourth-form school children in New Zealand.

AIMS: To determine the prevalence of cigarette smoking in 14 and 15 year old school children in New Zealand and to examine associated risk factors. METHODS: Nationwide cross-sectional survey of fourth-form school children in New Zealand by means of an anonymous self administered questionnaire in November 1992. RESULTS: Questionnaires from 14,097 fourteen and fifteen year-olds were analysed. 65.6% had tried smoking, and 36.1% regarded themselves as smokers. Females and Maori had significantly higher prevalence rates. Of Maori females 44.6% were current smokers (more than one per month) compared to 24.0% for the whole group, and 33.0% were daily smokers. Pacific Island students, who have similar socioeconomic disadvantage to Maori, have a lower relative risk of smoking (RR) 0.79, (95% confidence interval (CI) 0.68, 0.91), than Europeans. Major independent risk factors were identified and population attributable risk was calculated for parental smoking (22.9%), poor knowledge of adverse health effects (7.3%) and watching televised sports (13.4%). These three modifiable factors accounted for 36.1% of the total smoking prevalence in these children. CONCLUSION: The continued high prevalence of smoking in New Zealand children, especially in Maori and in females, prove current public health measures to be inadequate. Our results suggest that strategies aimed at decreasing parental smoking, improving student knowledge of adverse health effects and preventing tobacco sponsorship of television sports could greatly decrease the smoking prevalence in this age group.

Adolescent

Public health policy on bed sharing and smoking in the sudden infant death syndrome.

AIMS: Further develop New Zealand public health policy on infant bed sharing by quantifying the number of sudden infant death syndrome (SIDS) cases attributable to bed sharing among infants of smoking and nonsmoking mothers. METHODS: A large nation-wide case control study covering a region with 78% of all births in New Zealand during 1987-90. Interviews were completed with parents of 393 (81.0% of total) cases who died from the sudden infant death syndrome in the postneonatal age group, and 1592 (88.4% of total) controls who were a representative sample of all hospital births in the study region. RESULTS: The proportion of control infants who usually bed shared in the last 2 weeks was 65.7% in Maori, 73.7% in Pacific Island people and 35.5% in Europeans (44.5% in all ethnic groups combined, and half of these for less than 2 hours per night). There was an interaction between maternal smoking and infant bed sharing on the risk of sudden infant death separately in Maori, Pacific Island and European infants with the risk being highest in infants exposed to both risk factors. 26% of SIDS deaths were explained by bed sharing among infants of smoking mothers (who comprised 16% of the total infant population) and 3% by bed sharing among infants of non-smoking mothers (28% of total infant population). CONCLUSION: Infant bed sharing is common. The majority of SIDS deaths that are attributed to be sharing occur among infants of smoking mothers. A policy which advises all infants not to bed share is estimated to potentially save an extra 3% of SIDS compared to a policy targeted only on infants of smoking mothers. If public attitudes are favorable to bed sharing, there could be a marginal cost (against its acceptance) by including infants of non-smoking mothers in the recommendation not to bed share. These findings should not be interpreted as indicating that bed sharing where the mother is a nonsmoker is safe or protective against SIDS.

Beds