A systematic review and meta-analysis of interventions for weight management using text messaging.

BACKGROUND: Obesity prevalence continues to increase worldwide, with significant associated chronic disease and health cost implications. Among more recent innovations in health service provision is the use of text messaging for health behaviour change interventions including weight management. This review investigates the efficacy of weight management programmes incorporating text messaging. METHODS: Medical and scientific databases were searched from January 1993 to October 2013. Eligibility criteria included randomised controlled trials (RCTs), pseudoRCTs and before and after studies of weight management, among healthy children and adults, that used text messaging and included a nutrition component. Data extraction and quality assessment followed guidelines from PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) and the Evidence Analysis Manual of the American Academy of Nutrition and Dietetics. RESULTS: From 512 manuscripts retrieved, 14 met the inclusion criteria (five manuscripts in children and nine in adults). Duration of interventions ranged from 1 to 24 months. Frequency of text messaging was from daily to fortnightly. Six studies in adults were included in a meta-analysis with mean body weight change as the primary outcome. The weighted mean change in body weight in intervention participants was -2.56 kg (95% confidence interval = -3.46 to -1.65) and in controls -0.37 kg (95% confidence interval = -1.22 to 0.48). CONCLUSIONS: The small body of evidence indicates that text messaging interventions can promote weight loss. However, lack of long-term results indicate that further efficacy studies are required. Future investigations should elucidate the determinants, such as intervention duration, text message frequency and level of interactivity that maximise the success and cost effectiveness of the delivery medium.

Lifestyle intervention for preventing weight gain in young adults: a systematic review and meta-analysis of RCTs.

Younger generations of Australians are gaining weight faster than their parents. Associated health consequences are likely to ensue unless weight gains are prevented; however, it is unclear how to effectively intervene in this population. Electronic databases for health sciences were searched from April to the end of August 2011. Nine studies were included in the review, eight in the meta-analysis, from 771 abstracts reviewed for eligibility criteria: randomized controlled trials of lifestyle interventions, published in English (1980 onward), aimed at preventing weight gain among healthy subjects 18-35 years. Mean body weight change was the primary outcome. The combined weighted mean change in intervention participants was -0.87 kg (95% CI -1.56, -0.18) and in control participants 0.86 kg (95% CI 0.14, 1.57). Post hoc meta-regression analyses revealed evidence-based interventions of 4 months or longer duration were significantly associated with greater weight loss (-1.62 [95% CI -3.21, -0.04], P = 0.045). The small number, short duration and large heterogeneity of trials means the effectiveness of lifestyle intervention for preventing young adult weight gain remains unclear. Future trials conducted over longer periods with larger samples are urgently required to develop effective programmes that will protect against weight gains in future generations.

Age, period and birth cohort effects on prevalence of overweight and obesity in Australian adults from 1990 to 2000.

OBJECTIVE: To assess the individual contributions of age, period and birth cohort to prevalence of overweight and obesity in the Australian population during 1990 to 2000. DESIGN: Age-period-cohort Poisson regression modelling of data from National Health Surveys conducted in Australia in 1990, 1995 and 2000. SUBJECTS: Adults aged 20 years and over. Weightings were applied to account for differences in sampling and participation rates so that the sample is representative of the entire Australian adult population. METHODS: Twelve age groups, based on 5-year intervals from 20 to 24 years to greater than 75 years, three survey periods and 14 cohorts, also based on 5-year intervals from pre-1915 up to 1976-1980, were used in the analysis. The data were age-standardized to the 2000 population and body mass index (BMI) was calculated. Log-linear models, for the prevalence rates of overall overweight (BMI > or =25) and of obesity (BMI > or =30) were fitted to the data. RESULTS: Age (P<0.001), period (P<0.001) and cohort (P=0.002) all showed significant independent effects on prevalence of overall overweight in the Australian population such that prevalence rises with increasing age, recency of period and cohorts born since 1960. Age (P<0.001) and period (P<0.001) demonstrated strong effects on prevalence of obesity but birth cohort (P=0.07) was not significant. The effects were similar for men and women except that the overall effect of birth cohort on overall overweight was significant in women (P<0.05) but not men (P=0.09). CONCLUSION: The prevalence of overweight and obesity in Australian adults continued to rise during the 1990s. The obesogenic environment seems to have worsened and more recently born cohorts may be at increased risk of overweight.

Body mass index, physical activity and dietary behaviours among adolescents in the Kingdom of Tonga.

OBJECTIVES: To compare the prevalence of overweight and obesity among adolescents using international and ethnic-specific cut-off points and to examine patterns of physical activity and dietary behaviours. DESIGN: Cross-sectional analytical study. SETTING: Schools on Tongatapu, Vava'u and Hapa'ai islands in the Kingdom of Tonga. SUBJECTS: A total of 443 school students aged 11-16 years underwent anthropometric measures of height and weight and provided self-reported measures of physical activity and dietary behaviours. Results Mean body mass index (BMI) was higher among girls than boys (23.7 kg m(-2) vs. 21.8 kg m(-2) and tended to increase with age. A total of 36.0% of boys and 53.8% of girls were overweight or obese using the international cut-off points, whereas 25.0% of boys and 37.6% of girls were classified in this way using Polynesian-specific cut-off points. Tinned mutton or beef was the food that most participants (56.9%) reported eating once or more per day. Over half of the young people did not eat taro, fruit or vegetables at least once per day. Regular physical activity outside of school hours was reported by 20.7% of respondents, and 58.2% watched 1 h or more of television per day. Physical activity participation was the only behaviour independently associated with a lower risk of overweight or obesity. Conclusions Using Polynesian-specific cut-off points for overweight and obesity the prevalence of these conditions was still among the highest found in adolescents. The prevalence of physical inactivity and poor dietary habits indicate that risk factors for chronic disease are well established during adolescence in Tonga.

Long-term changes in leisure time walking, moderate and vigorous exercise: were they influenced by the National Physical Activity Guidelines?

Data from the Australian Bureau of Statistics three cross-sectional National Health Surveys, conducted in 1989-1990, 1995-1996 and 2000, were used to examine long-term population responses to the 1996 physical activity (PA) recommendations. Past 2-week recall of the number of times and total minutes spent walking for recreation or sport, and doing moderate and vigorous exercise, were averaged for 1 week to create a measure of 'sufficiently active': >or=5 weekly sessions of >or=150 min/week of at least moderate-intensity activity. With the exception of adults aged>60 years, from 1989 to 2000, there were increases in the prevalence of walking (+8%) and in moderate-intensity exercise (+4%), resulting in a significant decline (-6%) in the proportion of those reporting no leisure-time exercise. Participation in vigorous exercise remained unchanged. There was a 'population shift' in median minutes and sessions of walking from 1995 to 2000, but the prevalence of regular walking (>or=5 times and >or=150 min/week) remained unchanged. A small but significant increase (+2%) in the proportion of adults who met the PA recommendations was noted mainly for men under 60 years and for women aged 45-59 years. The proportion meeting the PA recommendations declined significantly in the most socioeconomically disadvantaged area. These data provide evidence contrary to the observed declines in PA documented by the Active Australia surveillance in the late 1990s. The population may have responded to the 1996 concept of moderate-intensity exercise mainly by walking, but sustainable promotional efforts will be required to build on these gains in the forthcoming decades.

Mental disorders, disability and health service use amongst Vietnamese refugees and the host Australian population.

OBJECTIVE: To compare the prevalence of common mental disorders, disability and health service utilization amongst Vietnamese refugees resettled in Australia for 11 years, with data obtained from a national survey of the host population. METHOD: A stratified multistage probability household survey of 1611 Vietnamese undertaken in the state of New South Wales was compared with data from 7961 Australian-born respondents. Measures included the CIDI 2.1 and the MOS SF-12. RESULTS: The 12-month prevalence of anxiety, depression and drug and alcohol dependence amongst Vietnamese was 6.1% compared with 16.7% amongst Australians. Vietnamese with a mental illness reported higher disability but exhibited similar levels of mental health consultation. The overall service burden of mental disorders was lower for the Vietnamese. CONCLUSION: The findings suggest that refugee groups resettled for some time in Western countries may show sound mental health adaptation and do not necessarily impose a burden on general or mental health services.

Antecedents to hospital deaths.

BACKGROUND: Recent studies have suggested there are a large number of potentially preventable deaths in Australian hospitals. AIM: This study aimed to document antecedent factors in hospital deaths in an attempt to identify potentially preventative factors. METHODS: The study was conducted at three separate acute hospitals. Demographics of all deaths were recorded over a 6-month period as well as antecedent factors present within 0-8 and 8-48 h of all deaths including vital sign abnormalities, cardiorespiratory arrests and admission to intensive care. Separate analysis was performed on 'not for resuscitation' deaths. RESULTS: There were a total of 778 deaths, of which 549 (71%) were 'not for resuscitation'. There were 171 (22%) deaths preceded by arrest and 160 (21%) preceded by admission to intensive care. Of the remaining deaths, 30% had severely abnormal physiological abnormalities documented. This incidence was 50% in the non-do not resuscitate (DNR) subgroup. Concern about the patient's condition was expressed in the patient's notes by attending nursing staff and junior medical staff in approximately one-third of non-DNR deaths. Hypotension (30%) and tachypnoea (17%) were the most common antecedents in the non-DNR deaths. CONCLUSION: There is a high incidence of serious vital sign abnormalities in the period before potentially preventable hospital deaths. These antecedents may identify patients who would benefit from earlier intervention.

The reliability and validity of the physical activity questions in the WHO health behaviour in schoolchildren (HBSC) survey: a population study.

OBJECTIVE: To assess the test-retest reliability and validity of the physical activity questions in the World Health Organisation health behaviour in schoolchildren (WHO HBSC) survey. METHODS: In the validity study, the Multistage Fitness Test was administered to a random sample of year 8 (mean age 13.1 years; n = 1072) and year 10 (mean age 15.1 years; n = 954) high school students from New South Wales (Australia) during February/March 1997. The students completed the self report instruments on the same day. An independent sample of year 8 (n = 121) and year 10 (n = 105) students was used in the reliability study. The questionnaire was administered to the same students on two occasions, two weeks apart, and test-retest reliability was assessed. Students were classified as either active or inadequately active on their combined responses to the questionnaire items. Kappa and percentage agreement were assessed for the questionnaire items and for a two category summary measure. RESULTS: All groups of students (boys and girls in year 8 and year 10) classified as active (regardless of the measure) had significantly higher aerobic fitness than students classified as inadequately active. As a result of highly skewed binomial distributions, values of kappa were much lower than percentage agreement for test-retest reliability of the summary measure. For year 8 boys and girls, percentage agreement was 67% and 70% respectively, and for year 10 boys and girls percentage agreement was 85% and 70% respectively. CONCLUSIONS: These brief self report questions on participation in vigorous intensity physical activity appear to have acceptable reliability and validity. These instruments need to be tested in other cultures to ensure that the findings are not specific to Australian students. Further refinement of the measures should be considered.

The epidemiology of overweight and obesity among Australian children and adolescents, 1995-97.

OBJECTIVES: To determine the population prevalence of overweight and obesity among Australian children and adolescents, based on measured body mass index (BMI). To determine if overweight and obesity are distributed differentially across the population of young Australians. METHODS: Data from three independent surveys were analysed. In each, height and weight were measured by trained surveyors using valid, comparable methods. BMI (kg/m2) was used as the index of adiposity and recently published international BMI cut-off values used to categorise each subject as non-overweight, overweight or obese. RESULTS: The population prevalence and distribution of overweight, obesity and overweight/obesity combined were generally consistent across datasets. The ranges of the prevalence of non-overweight, overweight, obesity and overweight/obesity combined were 79-81%, 14-16%, 5% and 19-21% (boys) respectively and 76-79%, 16-18%, 5-6% and 21-24% (girls). There were no consistent relationships between the prevalence of overweight/obesity and sex, age or SES. Their prevalence was up to 4% higher in urban than rural areas among boys, but there were no differences between urban and rural girls. The data suggest a higher prevalence of overweight/ obesity among students from European or Middle-Eastern cultural backgrounds. CONCLUSIONS: Some 19-23% of Australian children and adolescents are either overweight or obese. Although urban/rural, SES and cultural background differentials were noted, only the last warrants a targeted health promotion response. IMPLICATIONS: Overweight/obesity is a prevalent health risk factor among Australian children and adolescents. More information is needed to understand whether targeted approaches are required for specific ethnic groups in addition to broad, population-based approaches.

Rates of in-hospital arrests, deaths and intensive care admissions: the effect of a medical emergency team.

OBJECTIVES: To evaluate the effectiveness of a medical emergency team (MET) in reducing the rates of selected adverse events. DESIGN: Cohort comparison study after casemix adjustment. PATIENTS AND SETTING: All adult (> or = 14 years) patients admitted to three Australian public hospitals from 8 July to 31 December 1996. INTERVENTION STUDIED: At Hospital 1, a medical emergency team (MET) could be called for abnormal physiological parameters or staff concern. Hospitals 2 and 3 had conventional cardiac arrest teams. MAIN OUTCOME MEASURES: Casemix-adjusted rates of cardiac arrest, unanticipated admission to intensive care unit (ICU), death, and the subgroup of deaths where there was no pre-existing "do not resuscitate" (DNR) order documented. RESULTS: There were 1510 adverse events identified among 50 942 admissions. The rate of unanticipated ICU admissions was less at the intervention hospital in total (casemix-adjusted odds ratios: Hospital 1, 1.00; Hospital 2, 1.59 [95% CI, 1.24-2.04]; Hospital 3, 1.73 [95% CI, 1.37-2.16]). There was no significant difference in the rates of cardiac arrest or total deaths between the three hospitals. However, one of the hospitals with a conventional cardiac arrest team had a higher death rate among patients without a DNR order. CONCLUSIONS: The MET hospital had fewer unanticipated ICU/HDU admissions, with no increase in in-hospital arrest rate or total death rate. The non-DNR deaths were lower compared with one of the other hospitals; however, we did not adjust for DNR practices. We suggest that the MET concept is worthy of further study.

Acute effects of low levels of ambient ozone on peak expiratory flow rate in a cohort of Australian children.

BACKGROUND: We enrolled a cohort of primary schoolchildren with a history of wheeze (n = 148) in an 11-month longitudinal study to examine the relationship between ambient ozone concentrations and peak expiratory flow rate. METHODS: Enrolled children recorded peak expiratory flow rates (PEFR) twice daily. We obtained air pollution, meteorological and pollen data. In all, 125 children remained in the final analysis. RESULTS: We found a significant negative association between daily mean deviation in PEFR and same-day mean daytime ozone concentration (beta-coefficient = 0.88; P = 0.04) after adjusting for co-pollutants, time trend, meteorological variables, pollen count and ALTERNARIA: count. The association was stronger in a subgroup of children with bronchial hyperreactivity and a doctor diagnosis of asthma (beta-coefficient = -2.61; P = 0.001). There was no significant association between PEFR and same-day daily daytime maximum ozone concentration. We also demonstrated a dose-response relationship with mean daytime ozone concentration. CONCLUSIONS: Moderate levels of ambient ozone have an adverse health effect on children with a history of wheezing, and this effect is larger in children with bronchial hyperreactivity and a doctor diagnosis of asthma.

Assessing need in a privately insured population--the MBF Preventive Health Survey.

A self-administered mailed questionnaire was used to assess the health behaviours and health status of a random sample of members of the Medical Benefits Fund of Australia Limited (MBF). The data reaffirmed that the privately insured were more likely to have lower levels of major health risks and to practise better prevention than the uninsured. The survey was useful as a planning tool for MBF, confirming areas of preventive health that were already taken seriously by MBF members. Given the social advantages of these privately insured people, the results may also point to optimal health promotion and disease prevention rates expected in a population.

Validation of a predictive model for asthma admission in children: how accurate is it for predicting admissions?

We studied 364 index presentations to the Emergency Department of a children's hospital with a diagnosis of asthma. The admission rate for this group of children was about 31%. We developed a parsimonious multiple logistic regression model to predict asthma hospital admission based on asthma severity indicators. We then evaluated the model's predictive ability using two methods of cross-validation, using the same sample that was used for the predictive model, and using data from a split sample. The logistic regression model had a predictive accuracy of 90% (95% confidence interval 85-95%). The sensitivity and specificity were 86% and 88%, respectively. Cross-validation models confirmed that the predictive ability of the model was stable. In studies with limited sample sizes, it is possible to validate a model without setting aside a split sample for cross-validation.

Socio-economic, migrant and geographic differentials in coronary heart disease occurrence in New South Wales.

OBJECTIVE: This study examines the variation in coronary heart disease (CHD) mortality and acute myocardial infarction (AMI) by socio-economic status (SES), country of birth (COB) and geography (urban/rural) in the total population of New South Wales (Australia) in 1991-95. METHOD: CHD deaths and AMI are from complete enumerations of deaths and hospital admissions, respectively; and population denominators are from census information. Data are examined separately by sex, and comparisons of SES groups (based on municipalities), COB and region are analysed using Poisson regression, after adjustment for age. RESULTS: The study identified higher risk for AMI admissions and CHD mortality in lower SES populations with significant linear trends, for both sexes, adjusted for age, region and COB. According to the population attributable fractions (PAF), 23-41% of the risk of CHD occurrence is due to SES lower than the highest quartile. The higher age-adjusted risk for CHD occurrence in rural and remote populations for both sexes, compared with urban communities, was lessened by adjustment for COB, and all but abolished when also adjusted for SES.COB analysis indicated significantly lower age-adjusted AMI admissions and CHD mortality compared with the Australian-born. CONCLUSIONS: Higher risks for CHD in rural populations compared with the capital city (Sydney) are due, in part, to lower SES, lesser migrant composition. IMPLICATIONS: Strategies for reducing CHD differentials should consider demographic factors and the fundamental need to reduce socio-economic inequalities, as well as targeting appropriate prevention measures.

Risk factors for asthma deaths: a population-based, case-control study.

OBJECTIVES: To investigate risk factors for death from asthma using a case-control study design with two control groups. METHODS: Cases (n = 42) comprised subjects aged 10-59 years who died from asthma. Two control groups were selected: a random sample of asthmatics from the community (n = 132) and age and sex matched patients recently admitted to hospital for asthma (n = 89). We obtained information from proxies of cases and controls, and their general practitioners, by a structured telephone survey. Matched and unmatched logistic regression analyses were used to determine odds ratios for risk factors for asthma deaths. RESULTS: Compared to community controls, important risk factors for asthma deaths included indicators of asthma severity, use of three or more groups of asthma medications, more extensive use of health services for asthma, poor compliance with asthma medications and regularly missing hospital and general practitioner appointments for asthma. Compared to hospital controls, risk factors for asthma deaths were previous visits to emergency department for asthma, knowledge about asthma medications and regularly missing general practitioner appointments. CONCLUSIONS: In this study, severity of asthma, increased health service utilisation and suboptimal asthma self-management were associated with increased risks for asthma death. IMPLICATIONS: People with severe asthma or poorly controlled asthma have a greater risk of dying from their asthma. Both clinicians and non-clinicians managing asthma should regularly assess the appropriateness of management to prevent deaths.

Admission rates as an indicator of the prevalence of severe asthma in the community.

BACKGROUND: A reliable indicator of the prevalence of severe asthma in the community is needed to monitor population-based asthma control strategies. We examined the potential use of asthma admissions to hospital as such an indicator. METHODS: We recruited subjects from the Emergency Department (ED) of a children's hospital. The attending doctor completed the 'physician questionnaire' which included questions on the patient's asthma severity and interval severity/chronicity of asthma. The parent/guardian completed the 'parent questionnaire'. It included questions on demography, asthma knowledge and attitudes, asthma history and social support. We performed univariate and multiple logistic regression to determine predictors for hospital admission. RESULTS: Interval severity of asthma, pre-treatment severity of wheeze and low post-treatment pulse oximetry best predicted whether children presenting with asthma were admitted. Demographic variables, factors associated with access to health services and factors related to the asthma history and management were not significant predictors of admission. DISCUSSION: At the population level, it may be possible to utilise routine hospital admission rates as an indicator of the prevalence of severe asthma in the community, especially within the context of monitoring trends in asthma prevalence. Our study was conducted in a metropolitan tertiary paediatric hospital. The reliability of hospital admission rates as indicators of the prevalence of severe asthma in other hospital settings, in different population groups and over time remains to be established.

A population-based survey of immunization coverage in children aged 2 years and younger in New South Wales.

OBJECTIVE: To provide a population-based baseline of immunization rates in children aged 2 years and younger in New South Wales (NSW) in 1992, permitting more accurate evaluation of the efficacy of current programmes. METHODS: A cross-sectional population-based survey of 622 households from areas resident to over 73% of all children aged 4 years and younger in NSW. RESULTS: Of the 322 households with children aged 3-24 months, 212 (66%; confidence interval (CI): 57-75%) were up-to-date with the recommended immunization schedule, 68 (21%; CI: 15-27%) had not commenced any immunization, and 42 (13%; CI: 9-17%) were partially immunised. Ability to read English (odds ratio (OR): 5.43; CI: 2.37-12.44) and receipt of hepatitis B immunization (OR; 2.54; CI: 1.27-5.07%) were highly associated with up-to-date immunization; whilst a history of any illnesses, frequent doctor visits in the past 12 months (OR: 0.47; CI: 0.27-0.85%) and older age (16-24 months) (OR: 0.26; CI: 0.12-0.50%) were less likely to be associated with up-to-date immunization. CONCLUSIONS: In 1992 NSW had low levels of up-to-date immunization. Significantly, one-fifth of NSW families with children aged 3-24 months did not have a record of any immunizations. This could not be explained by delay in commencing immunization. Poor competency in reading English was strongly associated with failure to immunise, suggesting that there had been inadequate targeting of immunization campaigns in non-English-speaking communities.

Prevalence and associations of epiretinal membranes. The Blue Mountains Eye Study, Australia.

PURPOSE: The purpose of the study is to determine the prevalence and associations of epiretinal membranes in a defined older Australian population and to assess their influence on visual acuity. METHODS: Three thousand six hundred fifty-four persons 49 years of age or older, representing 88% of permanent residents from an area west of Sydney, underwent a detailed eye examination, including stereo retinal photography. Epiretinal membranes were diagnosed clinically and from photographic grading. RESULTS: Signs of epiretinal membranes were found in 243 participants (7%; 95% confidence interval [CI], 6.1, 7.6), bilateral in 31%. The prevalence was 1.9% in persons younger than 60 years of age, 7.2% in persons 60 to 69 years of age, 11.6% in persons 70 to 79 years of age, and 9.3% in persons 80 years of age and older, with slightly higher rates in women. Two stages were identified: an early form without retinal folds, termed "cellophane macular reflex" present in 4.8%, and a later stage with retinal folds, termed "preretinal macular fibrosis" (PMF), found in 2.2% of the population. Preretinal macular fibrosis, but not cellophane macular reflex, had a small, significant effect on visual acuity. Preretinal macular fibrosis was significantly associated with diabetes, after age-gender adjustment, in subjects without signs of diabetic retinopathy (odds ratio, 3.2; 95% CI, 1.4, 7.2). Preretinal macular fibrosis also was associated with increased fasting plasma glucose (odds ratio, 1.2; 95% CI, 1.1, 1.3). Epiretinal membranes were found in 16.8% of persons who had undergone cataract surgery in one or both eyes (including PMF in 3.7%), in 16.1% of retinal vein occlusion cases (PMF in 12.5%), both significantly higher rates than in subjects without these conditions (P < 0.0001), and in 11% of persons with diabetic retinopathy (PMF in 3.6%), not significantly higher (P = 0.17). CONCLUSIONS: This study has documented the frequency and mild effect on vision of epiretinal membranes in an older population. Diabetes was associated significantly with idiopathic cases, whereas well-known associations with past cataract surgery and retinal disease were confirmed.

Open-angle glaucoma and diabetes: the Blue Mountains eye study, Australia.

PURPOSE: The authors explore the relationship between diabetes and open-angle glaucoma in a defined older Australian population. METHODS: Three thousand six hundred fifty-four people 49 to 96 years of age, living west of Sydney, underwent a detailed eye examination. This included automated perimetry, stereo optic disc photographs, and applanation tonometry; in addition, fasting plasma glucose levels were ascertained. Glaucoma was diagnosed if matching visual field and optic disc cupping were present, without reference to intraocular pressure (IOP) level. Ocular hypertension (OH) was diagnosed if IOP in either eye was > or = 22 mm and glaucomatous disc and visual field changes were absent. RESULTS: Glaucoma prevalence was increased in people with diabetes, diagnosed from history or elevated fasting plasma glucose level (5.5%), compared with those without diabetes (2.8%; age-gender adjusted odds ratio [OR] 2.12, 95% confidence intervals [CI] 1.18-3.79). Ocular hypertension was also more common in people with diabetes (6.7%), compared with those without diabetes (3.5%; OR 1.86, CI 1.09-3.20). Diabetes was present in 13.0% of people with glaucoma, compared with 6.9% of those without glaucoma. This increase was highest for previously diagnosed glaucoma cases (16.7%; OR 2.82, CI 1.35-5.87). However, in 67% of such cases, glaucoma was diagnosed before the diabetes. For those not receiving glaucoma treatment, IOP was consistently slightly higher in people with diabetes, with the age-gender adjusted mean IOP 0.6 mm higher. CONCLUSIONS: The significant and consistent association between diabetes and glaucoma found in our study, which appeared independent of the effect of diabetes on IOP, suggests that there is a real association between these two diseases.

Increasing response rates in telephone surveys: a randomized trial.

BACKGROUND: Sampling frames and mode of contact and administration of questionnaires are important factors contributing to response rates and selection bias in population-based research. The purpose of this paper is to evaluate whether contact by mail before contact by telephone increases response rate, and to assess the concurrent validity of telephone surveys for collecting health research and service data. METHODS: Two thousand households were randomly selected from electronic white pages. Half were randomly allocated to receive or not to receive an explanatory letter before telephone contact. Interviewers were blinded to whether a household received a letter. Respondents aged 18 years or over were randomly selected from within each household using a Kish grid and interviewed by telephone. RESULTS: The overall response rate was 68 per cent [confidence interval (CI) 66-70]. The response rate of those who received the letter was 76 per cent (CI 73-79), and of those who did not receive the letter was 60 per cent (CI 56-63). Use of the Kish grid to select randomly a respondent decreased the response rate by less than 10 per cent. The internal validity of the data was as follows: in a 10 per cent sub-sample, the Kish grid had been correctly applied in 93 per cent of households, and in 99 per cent of households the exclusion criteria had been correctly adhered to. The external validity was as follows: comparisons with data obtained from the same reference population using similar instruments administered face-to-face revealed no meaningful or significant differences in population estimates. CONCLUSIONS: Mail-out before telephone contact greatly increases response rates at low cost. Telephone surveys can yield valid, useful data for health research and service evaluation.