Body mass index versus waist circumference as predictors of mortality in Canadian adults.

BACKGROUND: Elevated body mass index (BMI) and waist circumference (WC) are associated with increased mortality risk, but it is unclear which anthropometric measurement most highly relates to mortality. We examined single and combined associations between BMI, WC, waist-hip ratio (WHR) and all-cause, cardiovascular disease (CVD) and cancer mortality. METHODS: We used Cox proportional hazard regression models to estimate relative risks of all-cause, CVD and cancer mortality in 8061 adults (aged 18-74 years) in the Canadian Heart Health Follow-Up Study (1986-2004). Models controlled for age, sex, exam year, smoking, alcohol use and education. RESULTS: There were 887 deaths over a mean 13 (SD 3.1) years follow-up. Increased risk of death from all-causes, CVD and cancer were associated with elevated BMI, WC and WHR (P<0.05). Risk of death was consistently higher from elevated WC versus BMI or WHR. Ascending tertiles of each anthropometric measure predicted increased CVD mortality risk. In contrast, all-cause mortality risk was only predicted by ascending WC and WHR tertiles and cancer mortality risk by ascending WC tertiles. Higher risk of all-cause death was associated with WC in overweight and obese adults and with WHR in obese adults. Compared with non-obese adults with a low WC, adults with high WC had higher all-cause mortality risk regardless of BMI status. CONCLUSION: [corrected] BMI and WC predicted higher all-cause and cause-specific mortality, and WC predicted the highest risk for death overall and among overweight and obese adults. Elevated WC has clinical significance in predicting mortality risk beyond BMI.

Relationship of magnesium intake and other dietary factors to blood pressure: the Honolulu heart study.

Associations between blood pressure and intakes of 61 dietary variables assessed by 24-h recall method were investigated in 615 men of Japanese ancestry living in Hawaii who had no history of cardiovascular disease or treated hypertension. Magnesium, calcium, phosphorus, potassium, fiber, vegetable protein, starch, vitamin C, and vitamin D intakes were significant variables that showed inverse associations with blood pressure in univariate and a multivariate analyses. Magnesium had the strongest association with blood pressure, which supports recent interest in its relation to blood pressure. Nevertheless, it was not possible to separate the effect of magnesium from that of other variables because of the problem of high intercorrelation among many nutrients. While recommendations based upon cross-sectional studies must be viewed cautiously, these results suggest that foods such as vegetables, fruits, whole grains, and low-fat dairy items are major sources of nutrients that may be protective against hypertension.

Environmental sensitivities: prevalence of major symptoms in a referral center: the Nova Scotia Environmental Sensitivities Research Center Study.

Although the phenomenon of environmental sensitivities (ES) has no clear etiology nor well-accepted pathophysiology, affected individuals experience symptoms that cause varying levels of dysfunction. Through a dedicated, government-funded research and treatment center, a detailed questionnaire covering 217 symptoms in 13 systems was mailed in 1997-1998 to 812 individuals referred to the center by physicians. A total of 385 (47%) questionnaires were returned, and data were analyzed on 351 individuals. Participants tended to be women (80%), middle-aged individuals (37% age 40-49 years), and those in higher educational groups (28% completed university), but there was wide variation in demographic variables. General symptoms such as difficulty concentrating, fatigue, forgetfulness, and irritability dominated the overall prevalence of symptoms since the start of their illness. Those related to irritation such as sneezing, itchy or burning eyes, and hoarseness or loss of voice were more common after exposure to environmental irritants. Ranking of symptoms using severity scores was consistent between men and women. Overall scores were higher in women, in participants who were separated or divorced, and in low-income groups. The type and consistency of symptoms experienced after exposure to triggering substances may not fit a purely psychogenic theory.

Reduced measles immunity in infants in a well-vaccinated population.

The recommended age for measles vaccination is based in part on information gathered when most mothers had natural measles. Nowadays many mothers have received measles vaccine. To assess this change measles antibody neutralization titers (NT) were determined for 278 mother-infant pairs. One hundred sixty-four mothers, born before 1958, likely had had natural measles (Group 1). Sixty mothers received one to three killed plus one attenuated measles vaccination (Group 2) and 54 received 1 attenuated measles vaccination only (Group 3). NT were determined for the mother and for the infant at birth and in the infant during the fourth and sixth months. Group 1 mothers and infants at every age had higher geometric mean NT than those in Groups 2 or 3 (P less than 0.05). By 7 months 65% of Group 1 infants and greater than 90% of Group 2 and 3 infants had an NT less than 1:10. The rate of antibody decay was significantly faster for Group 1 infants (P less than 0.05). Earlier vaccination in the infant should be considered.

Potential bias due to prevalent diseases in prospective studies.

In prospective studies, subjects found to have the disease under investigation at the initial screening examination are commonly excluded from analyses. However, the possibility of bias due to prevalent conditions other than the disease of interest is usually not considered. In the present study, an algebraic development enables analysis of the effects of inclusion and exclusion of subjects with certain prevalent conditions upon risk estimates. Hypothetical data are presented for which an association between a risk factor and an incident disease could become null or even reversed after removing subjects with certain prevalent diseases. Bias appears even when the only association present is between risk factor and total disease incidence. Data from the Honolulu Heart Study also have been used to illustrate this finding, examining the association between coronary heart disease (CHD) incidence and smoking. Decisions regarding the inclusion or exclusion of subjects with prevalent diseases requires prior knowledge of alteration of usual risk factors levels by individuals with these diseases. Simply removing all subjects with prevalent diseases might on the contrary create bias. Therefore, people with prevalent diseases should be screened for potential alteration of their risk factor levels as a result of the diseases. The situation becomes still more complex when several risk factors and prevalent diseases need to be considered at the same time as it happens in multivariate analyses. Because this situation represents a bias, and not confounding or effect modification, controlling for the effect of prevalent diseases is not appropriate.

Distribution of blood pressure and hypertension in Canada and the United States.

BACKGROUND: Two North American population based surveys, the Third National Health and Nutrition Examination Survey (NHANES III) and the Canadian Heart Health Surveys (CHHS) have similar time frames and methods that allow comparisons between these countries in terms of the distribution of systolic (SBP) and diastolic (DBP) blood pressure and the levels of hypertension awareness, treatment, and control. METHODS: Cross-sectional population surveys using similar methods conducted home interviews and clinic visits (CHHS), and medical examinations (NHANES III). The CHHS included the ten Canadian provinces (1986-1992) and NHANES III, a representative sample of the United States population (1988-1994). Blood pressure measurements were available for 23,111 Canadians (age 18-74 years), and restricted to the 15,326 US participants in the same age range (age 18-74 years) with both systolic and diastolic mean values. Standardized techniques were used for BP measurements. Mean of all available measurements was used from four measurements for the CHHS and six measurements for NHANES III. A mean SBP/DBP of 140/90 mm Hg or treated with medication defined hypertension. All measures were weighted to represent population values. RESULTS: Both surveys showed similar trends in mean BP by age, with slightly higher levels in the CHHS. Hypertension prevalence using the same definitions and the same age range (18-74 years) was NHANES III: 20.1%, CHHS: 21.1%. Although the prevalence of isolated systolic hypertension (ISH) was similar in both studies, around 8% to 9%, the CHHS had higher ISH prevalence than NHANES III in the younger age groups and lower prevalence in the older age groups. Elevated SBP dominated the prevalence figures after the 1950s in both studies. Compared to NHANES III, the CHHS showed a lower proportion (43% v 50%) of individuals with optimal BP (< 120/80 mm Hg) and a very low proportion of hypertensives under control (13% v 25%). About half of diabetic participants were hypertensive (using 140/90 mm Hg) in both countries with a very low level of control in Canada (9%) v the US (36%) for ages 18 to 74 years. CONCLUSIONS: The results of these two surveys highlight the importance of SBP, in the later decades of life, an overall low control of hypertension in both countries, and a better overall awareness, treatment, and control of hypertension in the US than in Canada for that period. Dissemination of hypertension guidelines and a more aggressive focus on SBP are urgently needed in Canada, with special attention to diabetics.

Awareness, treatment, and control of hypertension in Canada.

The Canadian Heart Health Surveys are cross-sectional, population-based cardiovascular disease risk factor surveys that took place in each of the 10 Canadian provinces between 1986 and 1992. Hypertension awareness, treatment, and control status are examined. Of 23,129 randomly selected, noninstitutionalized respondents aged 18 to 74 years, 85% had four blood pressure (BP) measurements taken under standardized conditions, two at home during a home interview and two at a following clinic visit. The mean of all available measurements was used to determine hypertension status. Estimates are weighted and represent population values. Only 2% of respondents had never had their BP checked, and 73% had had their BP checked in the last 12 months. A systolic or diastolic BP > or = 140/90 mm Hg was found in 22% of participants (26% of men, 18% of women), representing 4.1 million Canadians. Overall, 16% of participants were treated and controlled; 23% were treated and not controlled; 19% were not treated and not controlled; and 42% were unaware of their hypertension (47% of men and 35% of women). Among hypertensives 18 to 34 years old, 64% of men and 19% of women were unaware of their hypertension. Among treated and not controlled hypertensives 63% had a mean systolic BP > or = 150 mm Hg, and 29% a diastolic BP > or = 95 mm Hg, suggesting that an important number of Canadians treated for hypertension are still at increased risk. Despite frequent interactions with the health care system, too many Canadians are still not well controlled or are unaware of their hypertension.

Prevalence of cerebral palsy in Alberta.

BACKGROUND: In spite of scattered reports to the contrary, concern is continually expressed that the frequency of cerebral palsy has not decreased with modern perinatal/neonatal care. Overall, epidemiological information on cerebral palsy is scant. The generally accepted prevalence is 2 to 2.5 per thousand school-age children. METHODS: A population-based record linkage study of a presently living cohort of 96,359 children born from April, 1985 through March, 1988 and followed over an eight-year tracking period captured the diagnostic codes for all fee-for-service physician claims, all hospital separations and individual birth data from the Department of Vital Statistics of the Government of Alberta. The ICD-9 code "343" was used to identify subjects. The childhood prevalence and frequency by birthweight-specific sub-groups of cerebral palsy after age three years (congenital, 229 [92.3%]; probable acquired 19 [7.7%]) were identified giving an overall prevalence of 2.57 per 1000. Seventy percent were diagnosed before their third birthday. Cohort prevalence of cerebral palsy for low birthweight children (< 2500 grams) was 17.7, very low birthweight (< 1500 grams), 78.5; and extremely low birthweight (< 1000 grams), 98.4. Low birthweight children made up just over one-third of cases in this study. CONCLUSIONS: Cerebral palsy continues to affect a significant number of children suggesting the prevalence of cerebral palsy has not decreased. The proportion of affected children with low birthweight in this study is less than that reported in the literature.

The Alberta Heart Health Survey: methods and results.

OBJECTIVE: The Alberta Heart Health Survey is a population-based investigation of cardiovascular disease (CVD) risk factor prevalence and awareness among Albertans 18 to 74 years of age. DESIGN: A stratified, two-stage, replicated probability sample design developed by Statistics Canada was used to select 3437 individuals (2740 were located) from the Alberta Health Care Insurance Plan enrollment list. Trained community health nurses (n = 36) from 13 public health units conducted home interviews (n = 2237, response rate 82%) and subsequent clinic visits (n = 1993) from February to June 1990, using a core protocol common to similar studies conducted in other provinces, as part of the Canadian Heart Health Initiative. SETTING: The home interview collected data on individual and household demographic characteristics, smoking, alcohol consumption, physical activity, treatment and control of high blood pressure and high blood cholesterol, and family history of CVD. Clinic visits included blood collection for analysis of total plasma cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides; weight, height, waist and hip circumference, and two blood pressure measurements. Standardized protocols were used. Lipid analyses were conducted by the Lipid Research Laboratory, University of Toronto. Data management and analysis were conducted at the University of Alberta. MAIN RESULTS: The overall risk factor prevalence estimates were: high blood pressure 14%; smoking 27%; total cholesterol of at least 5.2 mmol/L, 36%; HDL cholesterol less than 0.9 mmol/L, 10%; LDL cholesterol of at least 3.4 mmol/L, 29%; body mass index 25 or more, 51%; sedentary lifestyle 37%. One or more of the three major risk factors (smoking, high blood pressure, high blood cholesterol) occurred in 57% (70% in those with 12 years of education or less). CONCLUSIONS: While the prevalence rates for the major risk factors are among the lowest in Canada, they are unacceptably high.

Comparison of the prevalence of cardiovascular risk factors between Quebec and other Canadian provinces: the Canadian heart health surveys.

OBJECTIVE: To compare the prevalence of different cardiovascular (CVD) risk factors between Quebec, a Canadian Province with a population of mainly French descendants, and other Canadian provinces. DESIGN: Cross-sectional surveys in the ten Canadian provinces using stratified, two-stage, replicated probability samples from health insurance registries. PARTICIPANTS: A total of 2,353 Quebec residents and 20,776 other Canadians aged 18 to 74 years were surveyed. INTERVENTION: Standardized interviews and measurement of CVD risk factors. RESULTS: Compared with other provinces, Quebec had a higher prevalence of smoking, (32% vs 25%), dyslipidemia (48% vs 43%), a similarly sedentary lifestyle (37% vs 38%), a lower prevalence of hypertension (19% vs 23%) and body mass index > or =27 (28% vs 33%). Prevalence of two of the above risk factors was greater in Quebec (29%) than in the other provinces (25%). The difference in the prevalence of dyslipidemia between Quebec and the other provinces remained after stratification by body mass index and smoking status. Combination of risk factors differed between Quebec and the other provinces. CONCLUSIONS: Different genetic backgrounds, cultural influences occurring at different times among different age groups, as well as different trends in CVD risk factors and their interaction may explain why cross-sectional surveys cannot fully explain the differences in CVD mortality between ethnic groups. Given these differences in CVD risk factors between Quebec and other provinces, the relatively high level of all risk factors in Canada justifies increased focus on the Canadian Heart Health Initiative and attention to regional and ethnic differences when addressing CVD risk factors.

Infant feeding practices in Ottawa-Carleton: the introduction of solid foods.

Infant feeding guidelines regarding the introduction of solid foods are generally not well known in Canada. The guidelines recommend that solid foods be introduced between four to six months of age, depending on the developmental readiness of the infant. In order to understand the underlying factors and patterns which contribute to the introduction of solid foods in infants, data were analyzed from three cross-sectional surveys of parents of six-month-old infants from the Ottawa-Carleton region (n = 373, 1988; n = 330, 1992; n = 338, 1996) conducted by the Ottawa-Carleton Health Department. Multivariable analysis showed that mothers who: did not breastfeed, were younger, had lower education, smoked or had partners that smoked, and lacked support after birth, were more likely to introduce solid foods before four months of age. These data support the need for nutrition education programs to increase adherence to the new Nutrition for Healthy Term Infants guidelines.

Prevalence of sexually transmitted diseases in juvenile prostitutes and street youth.

Four groups of adolescents - 35 juvenile prostitutes, 36 street youth, 31 monogamous sexually active adolescents and 35 non-sexually active adolescents - were studied between January 1, 1988 and December 31, 1988 for the presence of sexually transmitted diseases and other genital pathogens. The high prevalence of sexually transmitted diseases found in the juvenile prostitutes (Neisseria gonorrhoeae, 49%; Chlamydia trachomatis, 83%) is in contrast to other studies, which document much lower rates of infection. This could be due to the fact that there are few studies done on juvenile prostitutes as a well defined group. Despite high risk sexual behaviour, the consistent use of contraception was low. No contraceptives were used by 57% of the juvenile prostitutes and 85% of the street youth. None of the adolescents sought medical attention although 48% of the juvenile prostitutes and 53% of the street youth had genital symptoms. It appears that the present public health education and health care delivery do not reach this high risk population.

Perception of uncontrolled blood pressure and behaviours to improve blood pressure: findings from the 2009 Survey on Living with Chronic Diseases in Canada.

Individuals with hypertension should lower and maintain their blood pressure levels through lifestyle modification and/or pharmacotherapy. To determine whether perception of blood pressure control is related to behaviours and intentions for improving blood pressure, data from 6142 Canadians age 20+ years with self-reported hypertension were analysed. Relationships between perception of control, current behaviours for blood pressure control and intentions to improve these behaviours were examined. Although individuals who reported uncontrolled blood pressure were equally likely to report engaging in lifestyle behaviours for blood pressure control, they were more likely to indicate an intention to improve their health, compared with those who reported well-controlled/low blood pressure. These individuals were also less likely to report having enough information to control their blood pressure. In addition, they were less likely to report having been advised to take antihypertensive medication, and to be taking and adhering to medications. Individuals who perceive their blood pressure as uncontrolled have intentions to make health-enhancing changes but may lack the information to do so. The study highlights the potential need for programmes/services to help those with uncontrolled blood pressure make lifestyle changes and/or take appropriate medication.

Nutrition education practices and opinions of alberta family physicians.

A questionnaire was mailed to a random sample of 532 members of the Alberta Chapter of the College of Family Physicians in order to assess the role of physicians in providing nutrition education to their patients. Of the 255 respondents (53% response rate), over 97% agreed that "educating patients about nutrition is an important role for physicians." Physicians most often gave nutrition information on obesity, constipation, heart disease and hypertension, alcohol, coffee, infant feeding, osteoporosis, and prenatal nutrition. Female physicians gave nutrition information significantly more often than male physicians on four maternal and child health topics. Perceived barriers to nutrition education included lack of reimbursement for physicians (86%), lack of time (48%), and limited access to patient information (42%). Most physicians often informed patients on the seven most common nutrition topics despite these concerns.

A survey of physicians' uses/opinions regarding nutrition education resources.

Since physicians are one of the public's main sources of nutrition information, a study was conducted to investigate physicians' sources of nutrition knowledge, patient education resources, and opinions about potential nutrition services. A questionnaire was mailed to a random sample of family physicians. The response rate was 53% (n = 255). Fifty-three per cent of respondents ranked their personal knowledge and training as their most frequent source of nutrition information. The most widely reported sources of patient education resources were Health and Welfare Canada and industry. Physicians ranked resources from Health and Welfare Canada as highest for quality characteristics, and industry information as lowest. Pamphlets were ranked as the most/very useful patient service (70%), and physician reimbursement as the most useful physician service (59%). One-quarter of physicians asked for patient information on heart disease. The results of this study suggest physician reimbursement for nutrition education needs to be addressed by health insurance plans if physicians are to be expected to provide nutrition intervention. Further nutrition training for physicians should be conducted through medical education, continuing education and medical journals.

Chlamydia trachomatis genital infection.

OBJECTIVE: To determine family physicians' approaches to detecting, managing, and preventing genital Chlamydia trachomatis infection and their perceptions of barriers to prevention. To determine whether sex of physician is associated with differences in clinical approach to chlamydia, with levels of effort aimed at its prevention, and with perceived barriers to preventive efforts. DESIGN: Questionnaires were sent to a random sample of family physicians. SETTING: All health regions in Nova Scotia. PARTICIPANTS: Two hundred fifty-seven Nova Scotia family physicians. MAIN OUTCOME MEASURES: Responses to survey questions analyzed for association of practice behaviours with sex of physician. RESULTS: Response rate was 60%. Most physicians performed diagnostic tests for chlamydia on all patients. Responses indicated that 17% would test for C trachomatis during an annual Papanicolaou test in a low-risk 30-year-old, 61% would test a high-risk 21-year-old man, and 89% would test a pregnant 17-year-old. Therapies physicians might use were judged appropriate in 96% of responses. Only 51% indicated they would ever discuss false-positive test results with patients. Men physicians were less likely than women to ask 75% or more of their adolescent patients about sexual activity or to educate them about prevention of sexually transmitted diseases. Women physicians saw time and the fee schedule as less serious barriers to prevention than men did. CONCLUSIONS: Some physicians are not managing C trachomatis well. We should explore situations where gaps in performance are associated with sex of physician.

Comparison of esophageal, rectal, axillary, bladder, tympanic, and pulmonary artery temperatures in children.

Our objective was to determine the most reliable site for temperature measurement in children. In anesthetized children esophageal temperature readings were closest to those in the pulmonary artery (mean difference 0.1 degree C +/- 0.5 degree C compared with Genius tympanic thermometer (mean difference 0.6 degree C +/- 1.0 degree C), IVAC tympanic thermometer (mean difference 0.8 degree C +/- 1.0 degree C), rectal probe (mean difference 0.7 degree C +/- 1.7 degrees C), bladder probe (mean difference 0.9 degree C +/- 1.4 degrees C), and axillary probe (mean difference 1.3 degrees C +/- 1.3 degrees C).

A comparative evaluation of waist circumference, waist-to-hip ratio and body mass index as indicators of cardiovascular risk factors. The Canadian Heart Health Surveys.

OBJECTIVE: To comparatively evaluate cut-off points of waist circumference, body mass index and waist to hip ratio with respect to their ability to predict other individual and multiple cardiovascular disease risk factors. DESIGN: Population-based, cross-sectional surveys. SUBJECTS: A total of 9913 men and women aged 18-74, selected using health insurance registries from five Canadian provinces. MEASUREMENTS: Anthropometric measures, other cardiovascular risk factors, receiver operating characteristic curves, sensitivity, specificity, positive and negative predictive values. RESULTS: : Waist circumference may be the best single indicator of other individual and multiple cardiovascular risk factors. Optimal cut-off points of all anthropometric measures are dependent on age, sex and the prevalence of the risk factor(s) being considered. For waist circumference, cut-off points of > or =90 cm in men and > or =80 cm in women may be most appropriate for prediction of individual and multiple risk factors in Caucasian populations. CONCLUSION: Health professionals should incorporate the use of waist circumference measurements in their routine clinical examination of adult patients.

Success of a program of routine prenatal screening for hepatitis B surface antigen: the first 2 years.

Prenatal screening for hepatitis B surface antigen (HBsAg) restricted to women with defined risk factors for chronic hepatitis B virus (HBV) infection fails to identify many carriers. A centralized program of routine HBsAg screening for all pregnant women in Alberta was introduced in 1985. We collected and analysed data for the first 2 years of the program in Edmonton to determine the frequency of risk factors for HBsAg positivity, the proportion of multiparous HBsAg-positive women not identified in previous pregnancies, the efficiency and cost-effectiveness of providing immunoprophylaxis to infants at risk of HBV infection and the degree of success in inducing adequate protection. A total of 149 women (158 pregnancies) were found to be HBsAg positive. Risk factors were readily ascertainable for 85% of the women; the remaining 15% would not have been identified through risk-selective screening. The most common risk factors were Oriental ethnic origin, history of hepatitis, jaundice or multiple transfusions of blood or blood products, and occupational exposure to blood. Although 86% of the multiparous HBsAg-positive women had risk factors, only 7% had been identified in previous pregnancies. The Alberta program appears to be cost-effective. We conclude that only routine prenatal screening will identify all infants at risk of perinatal HBV infection and that a comprehensive public health program involving central laboratories, private physicians and public health staff can be highly effective and efficient in protecting infants against hepatitis B.