Variation by body mass index and age in waist-to-hip ratio associations with glycemic status in an aboriginal population at risk for type 2 diabetes in British Columbia, Canada.

BACKGROUND: It is unclear whether obesity and age modify or confound relations between abdominal adiposity and metabolic risk factors for type 2 diabetes. OBJECTIVE: Our objective was assess the consistency of relations between abdominal adiposity and glycemic variables across discrete categories of obesity and age. DESIGN: We performed a stratified analysis of prevalence data from a rural screening initiative in British Columbia, Canada. Subjects were Salishan Indians, all healthy relatives of individuals with type 2 diabetes [n = 151; age: 18-80 y; body mass index (BMI, in kg/m2): 17.0-48.2]. We measured waist-to-hip ratio (WHR) (2 categories); insulin, glycated hemoglobin (Hb A1c), and 2-h glucose concentrations (2 categories); and BMI (4 categories). BMI and age-specific odds ratios (ORs) and 95% CIs were calculated. RESULTS: WHR-glycemic variable relations were not consistent across BMI and age strata. Risks associated with high WHR were: for persons with BMIs from 25 to 29, elevated insulin (OR: 6.71; 95% CI: 1.41, 34.11) and Hb A1c (OR: 16.23; 95% CI: 2.04, 101.73) concentrations; for persons aged 18-34 y, elevated insulin concentrations [OR: indeterminate (+infinity); 95% CI: 1.89, +infinity]; and, for persons aged 35-49 y, elevated Hb A1c (OR: +infinity; 95% CI: 3.17, +infinity) and 2-h glucose (OR: 9.15; 95% CI: 1.74, 59.91) concentrations. CONCLUSIONS: WHR discriminates risk of type 2 diabetes in overweight but not obese individuals. Abdominal adiposity is associated with elevated insulin concentrations in younger age groups and with impaired glucose control in middle-aged groups, suggesting metabolic staging by age on a continuum from insulin resistance to impaired glucose tolerance.

Epidemiology of school injuries: a 2-year experience in a municipal health department.

School injuries occurring in a municipal school system during a 2-year period were reviewed to identify epidemiologic features of school injuries, to determine data requirements for ongoing injury surveillance, and to identify potential preventive strategies. Overall, 3,009 injuries were reported (2.82/100 students per year). Elementary school students had only a slightly higher rate (2.85) than secondary school students (2.78). However, the cause, nature, school location of injury, and body area injured formed distinct patterns in these two groups. Playgrounds were responsible for the highest overall and elementary school rates, whereas sports areas and classrooms had the highest rates among secondary school students. Falls were the most frequent cause of injury in elementary schools whereas, as expected, sports injuries were the most frequent cause among secondary school students. Contusions and abrasions of the head were the most frequent type of injury for both groups, although more common among elementary school students, whereas fractures, sprains, strains, and dislocations were more frequent among secondary school students. Although the proportion of severe injuries to secondary school students was slightly higher (39 v 35%), the rate of referral of students to a hospital or physicians among secondary school students (1.21 per 100 student-hours) was almost twice the rate of elementary school students (0.65 per 100 student-hours). Problems with definition of injury severity and the need to explore the social aspects of schools as a factor in injuries emerged as important considerations for future research.

Retinopathy of prematurity-induced blindness: birth weight-specific survival and the new epidemic.

A recent population-based study in the Canadian province of British Columbia showed that, since the mid-1960s, there has been a significant increase in the incidence of retinopathy of prematurity-induced blindness in infants weighing 750 to 999 g at birth. To determine the impact of changing birth weight-specific survival on this new epidemic, all infants born in the province in the period 1952 through 1986 and known to the British Columbia Health Surveillance Registry as having retinopathy of prematurity-induced blindness were identified. In addition, the birth registration records for the 1,299 740 infants born in British Columbia in the same period and the death records of the 22,940 British Columbia-born infants who died in the province before the end of their first year of life were linked using a combination of probabilistic and manual record linkage techniques. These linked records and the records from the Health Surveillance Registry were used to calculate birth weight-specific incidence rates of retinopathy of prematurity-induced blindness in liveborn infants and first-year-of-life survivors. The rates, in 5-year intervals, showed that, in both liveborn infants and first-year survivors, the highest birth weight-specific rates occurred during the first epidemic of retinopathy of prematurity, which ended in British Columbia in 1954. Since the mid-to late-1960s, the incidence of retinopathy of prematurity-induced blindness in liveborn infants weighing less than 1000 g increased steadily whereas in infants weighting 1000 to 1499 g, incidence decreased slightly since the original epidemic ended. However, the experience of first-year-of-life survivors is substantially different.(ABSTRACT TRUNCATED AT 250 WORDS)

Retinopathy of prematurity: a new epidemic?

This study provides the first empiric evidence for the existence of a new epidemic of retinopathy of prematurity-induced blindness. Data from a population-based register of handicapping conditions in the Canadian province of British Columbia, and a birth weight-specific census of live-born infants in British Columbia, were used to determine annual, population-level incidences of retinopathy of prematurity-induced blindness during 1952 to 1983. Changes in incidence since the end of the original epidemic (1954) were determined by subdividing the 29-year period (1955 to 1983) into two intervals (1955 to 1964 and 1965 to 1983). Standardized incidence ratio analyses revealed a marginally significant increase in the overall incidence of retinopathy of prematurity-induced blindness in the later as compared with the earlier period. Infants weighing 750 to 999 g at birth had a significantly increased standardized incidence ratio of 3.07 (95% confidence interval 1.26, 11.06). No increases in risk were observed in heavier or lighter weight infants. Because ascertainment and diagnostic changes do not explain the weight-specific increases in incidence, these results provide the first population-level evidence for a new epidemic.

The quick and the dead: "managing" inpatient care in British Columbia hospitals, 1969-1995/96.

OBJECTIVE: To examine changes in hospital use in British Columbia during a decade of capacity reductions. DATA SOURCES/STUDY SETTING: The data used are all separation records for British Columbia hospitals for the years 1969, 1978, 1985/86, 1993/94, and 1995/96. Separation records include acute care, rehabilitation, extended care, and surgical day care hospital encounters in British Columbia that were concluded during the years of interest. STUDY DESIGN: Analyses were based on per capita use of services for five-year age groups of the population to ages 90+; the emphasis was on looking at changes in the use of specific types of hospital services over the 26 years of study, with a particular focus on the most recent decade. DATA COLLECTION/EXTRACTION METHODS: Data were extracted from hospital separations files owned by the British Columbia Ministry of Health and housed at the Centre for Health Services and Policy Research. All separation records for the years of interest were included in the study. PRINCIPAL FINDINGS: Acute care use continued to fall over the last decade. The rate of decline increased during the last time period of study and affected seniors to the same degree as younger patients. At the same time, use of extended care decreased, compared to steady increases in earlier years. The result was that by 1995/96 nearly 40 percent of inpatient days were used by people who died in hospital, compared to 9 percent in 1969. These people, however, still represent a small proportion of separations. CONCLUSIONS: The "bed blocker" problem common to many hospital systems appears to have been largely alleviated in British Columbia over the decade 1985-95. The concurrent decrease in extended care use, however, makes it difficult to say where and how these people are now being cared for. Care for the dying has become a bigger issue for hospitals, but whether this is because of heroic interventions at the end of life is not clear. A "top-down," capacity-driven management approach to hospital use in British Columbia has produced effects that may seem familiar to those involved in more "bottom-up" managed care approaches in the United States.

Effectiveness of community-directed diabetes prevention and control in a rural Aboriginal population in British Columbia, Canada.

This report presents the process and summative evaluation results from a community-based diabetes prevention and control project implemented in response to the increasing prevalence and impact of non-insulin-dependent diabetes mellitus (NIDDM) in the Canadian Aboriginal population. The 24-month project targeted the registered Indian population in British Columbia's rural Okanagan region. A participatory approach was used to plan strategies by which diabetes could be addressed in ways acceptable and meaningful to the intervention community. The strategies emphasised a combination of changing behaviours and changing environments. The project was quasi-experimental. A single intervention community was matched to two comparison communities. Workers in the intervention community conducted interviews of individuals with or at risk for diabetes during a seven-month pre-intervention phase (n = 59). Qualitative analyses were conducted to yield strategies for intervention. Implementation began in the eighth month of the project. Trend measurements of diabetes risk factors were obtained for 'high-risk' cohorts (persons with or at familial risk for NIDDM) (n = 105). Cohorts were tracked over a 16-month intervention phase, with measurements at baseline, the midpoint and completion of the study. Cross-sectional population surveys of diabetes risk factors were conducted at baseline and the end of the intervention phase (n = 295). Surveys of community systems were conducted three times. The project yielded few changes in quantifiable outcomes. Activation of the intervention community was insufficient to enable individual and collective change through dissemination of quality interventions for diabetes prevention and control. Theory and previous research were not sufficiently integrated with information from pre-intervention interviews. Interacting with these limitations were the short planning and intervention phases, just 8 and 16 months, respectively. The level of penetration of the interventions mounted was too limited to be effective. Attention to process is warranted and to the feasibility of achieving effects within 24 months.

Socioeconomic status, mortality, and the development of cataract at a young age.

It has been hypothesized that senile cataract may serve as a marker for generalised tissue aging, since structural changes occurring in the proteins of the lens during cataract formation are similar to those which occur elsewhere as part of the aging process. An earlier analysis we carried out to test this hypothesis revealed a strong age-dependent relationship between undergoing cataract surgery and subsequent mortality. Relative risks for dying over 9 yr of follow-up were particularly increased for individuals who had developed cataract requiring operation between the ages of 50-65. This finding prompted us to test the hypothesis that younger patients undergoing surgery for cataract (those in which surgery was undertaken at 50-65 yr of age) would tend disproportionately to be resident in areas of generally lower socioeconomic status. A population-based linked health data resource containing data on all hospital separations in the province of British Columbia was used to examine this hypothesis. Linkage to Canadian census data was used to assign a socioeconomic decile to the area of residence for all individuals in British Columbia who either did, or did not, undergo cataract surgery over a 3 yr period, and were aged 50-95. Relative to those who resided in the highest socioeconomic areas, odds ratios for undergoing cataract surgery between 50 and 65 yr of age were significantly greater than 1 for the four lowest socioeconomic deciles. This association was observed despite a conservative bias in our setting that favoured those of higher socioeconomic status tending to receive earlier treatment. The results of this ecologic study prompt consideration of whether factors which have the dual attributes of being correlates of socioeconomic status and implicated in the development of cataract may play a role in mediating the processes involved in the well known association of socioeconomic status and mortality.

Research methods for surgeons: an overview.

The purpose of this paper is to outline a number of salient features in the design and conduct of clinical research in surgery. The key features emphasized are the need for clarity in the elaboration of study hypotheses, clear definition of the variables involved in the study, particularly the outcome variables, the need to confront the issue of bias and confounding, and a review of methodological issues associated with specific components in the research process. Particular attention is paid to patient selection, allocation of patients to experimental and control groups, randomization, problems of co-intervention and contamination, a brief discussion of analytic issues, and the critical importance of getting appropriate design and other methodological assistance prior to initiating a study. A short bibliography providing the reader with more in-depth discussions of the issues raised here is provided. It is the intention of this paper to introduce surgeons undertaking clinical research to these important methodological issues so that they can utilize appropriate consultative services more effectively.

Physicians and breastfeeding: beliefs, knowledge, self-efficacy and counselling practices.

A pilot-tested questionnaire was mailed to 325 obstetricians, pediatricians, family practitioners and general practitioners of a British Columbian maternity hospital to measure aspects relating to physicians' attitudes toward breastfeeding counselling. Response rate was 67.3%. The measures of self-efficacy, knowledge and beliefs were added to a regression model containing measures of gender, specialty, years in practice and personal or spousal breastfeeding experience to determine whether additional variance in counselling behaviour could be accounted for. Physicians attempted to convince women to breastfeed if: 1) they believed in the immune properties of breastmilk (OR = 1.23, SE = 0.07) and 2) they were confident in their own breastfeeding counselling (OR = 1.88, SE = 0.36). Likewise, encouraging women to continue breastfeeding in the face of breastfeeding problems was related to confidence in breastfeeding counselling (OR = 1.22, SE = 0.10) and belief in the immune properties of breastmilk (OR = 2.83, SE = 0.45).

Creating a population-based linked health database: a new resource for health services research.

As the availability of both health utilization and outcome information becomes increasingly important to health care researchers and policy makers, the ability to link person-specific health data becomes a critical objective. The integration of population-based administrative health databases has been realized in British Columbia by constructing an historical file of all persons registered with the health care system, and by probabilistically linking various program files to this 'coordinating' file. The linkages have achieved a high rate of success in matching service events to person-specific registration records. This success has allowed research projects to be proposed which would otherwise not have been feasible, and has initiated the development of policies and procedures regarding research access to linked data. These policies and procedures include a framework for addressing the ethical issues surrounding data linkage. With continued attention to confidentiality issues, these linked data present a valuable resource for health services research and planning.

A comparison of photoscreening techniques for amblyogenic factors in children.

We screened 236 consecutive patients aged 6 years or less using an Off-Axis photoscreener and an Otago-type photoscreener. With a masked standardized clinical assessment as the standard, an overall comparison of the results obtained with the two techniques revealed a sensitivity and specificity in the neighbourhood of 0.85 and 0.87 respectively for the Off-Axis photoscreener and 0.94 and 0.94 respectively for the Otago photoscreener. Both techniques, but especially the Off-Axis technique, were less sensitive and specific in younger children (24 months or less). Fundus colour (light or dark) did not greatly affect sensitivity or specificity. Photoscreening with the pupil dilated led to an increase in false-positive results with both techniques. Our results showed the Otago photoscreener to be superior in this clinical trial.

Field trial of the Otago photoscreener.

OBJECTIVE: To assess the effectiveness of the Otago photoscreener in detecting amblyogenic factors in the general population. DESIGN: Prospective clinical trial. SETTING: Suburban school district in Delta, BC. PARTICIPANTS: A total of 1245 kindergarten children. INTERVENTIONS: Screening for visual defects was done with the Otago photoscreener (by a technician) and the regular manual method (by a health care aide). A standard ophthalmologic examination was performed by a pediatric ophthalmologist and an orthoptist in a random sample of 20% of all children with normal results of screening (n = 241) plus all those with abnormal results (n = 29). MAIN OUTCOME MEASURES: Sensitivity, specificity, positive predictive value, rates of false-negative and false-positive results. RESULTS: The Otago screener had higher sensitivity than the manual technique (81% vs. 33%), especially for strabismus and cataracts. The specificity values of the two techniques were 98% and 97% respectively, and the positive predictive values were 77% and 54% respectively. The manual technique failed to identify 5.8% of children with visual defects, compared with 1.6% for the Otago screener. CONCLUSIONS: The Otago photoscreener is a superior instrument for identifying amblyogenic eye disease. However, given the relatively low yield, the value of any screening method should be assessed with regard to both costs and benefits.

Utilization management: a literature review for Canadian health care administrators.

Utilization management (UM), the attempt to measure, understand and reduce inappropriate hospital use, has been in development for over 20 years. It is an outgrowth of two related phenomena: (1) the increasing responsibility of large institutional third party payers for health care costs and the increasing demand of those payers for accountability; and (2) in Canada, particularly, the debate surrounding the adequacy of hospital funding and the perceived inadequacy of cost control using global budgeting. Given the interest in UM, hospital administrators, provincial and federal associations representing hospitals, hospital employees and physicians would find a review of UM programs useful in terms of what is known about their effectiveness, and the specific initiatives in Canada. The authors underscore the critical need for formal evaluation of UM programs; to date there has been little systematic research into issues related to its implementation and impact. This issue is particularly pertinent because UM programs have not been widely implemented in Canada.

Effect of older maternal age on birth outcomes in twin pregnancies: a population-based study.

OBJECTIVE: We compared perinatal mortality, preterm birth (<37, <33 and <28 weeks), small for gestational age (SGA), Apgar score (<4), mechanical ventilation (1 days) and prolonged neonatal intensive care unit (NICU) hospitalization (13 days) between twins of 25 to 34 and >35-year-old women. Further, we examined whether older maternal age effects were modified by parity or otherwise affected by chorionicity. STUDY DESIGN: We carried out a population-based retrospective cohort study including all twin births in British Columbia (BC), Canada, from 1999 to 2003. The BC perinatal database registry was used to obtain clinical, behavioral and demographic data. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were calculated using generalized estimating equation models. RESULT: Overall, twins of older women were more likely to be born preterm (<37 weeks), but not very or extremely preterm (<33 weeks). These twins were not at increased risk of perinatal death, mechanical ventilation or were not SGA compared with twins of younger women. Twins of older primiparous women did not have an elevated risk of NICU hospitalization; twins born to older multiparous women had higher risk (OR=1.8; 95% CI: 1.2 to 2.6). Analyses restricted to opposite-sex (dichorionic) twins showed that perinatal death, mechanical ventilation and very preterm birth occur less likely among older women (OR=0.2 (95% CI: 0.0 to 0.8), OR=0.3 (95% CI: 0.1 to 0.7) and OR=0.4 (95% CI: 0.2 to 0.7), respectively). Further, the risk of late preterm birth was increased and NICU hospitalization was reduced among opposite-sex twins born to older compared with younger primiparous women (OR=1.9 (95% CI: 1.3 to 2.8) and OR=0.2 (95% CI: 0.1 to 0.5), respectively). CONCLUSION: Twins of older mothers did not have an elevated risk for most adverse birth outcomes, except for late preterm birth. Risks of neonatal care admission may be elevated among older multiparous women.