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Biomedical subjects

D R MacLean

Publications and source records attributed to D R MacLean.

At least 19 recordsLinked to original sources
PubMed2002

Depressive symptoms predict medical care utilization in a population-based sample.

BACKGROUND: Several examinations have detected a relation between depressive symptoms and medical utilization. However, selection biases have been involved in most previous examinations. We sought to test the association between depressive symptoms and prospective, increased medical care utilization, in a population-based Canadian sample, while controlling for utilization due to medical illness and controlling for selection bias. METHODS: Data from the Nova Scotia Health Survey 1995, an age- and sex-stratified random sampling of 3227 Nova Scotian adults, included the Center for Epidemiological Studies-Depression scale and items assessing chronic medical conditions and current limitations in daily activities resulting from medical illness. We linked survey data with medical care utilization measures for the year following the survey, including out-patient visits, reimbursement for out-patient services, hospitalizations, and hospitalization days. RESULTS: After controlling for age, sex, count of medical diagnoses and current medical severity, those with a greater level of depressive symptoms were at greater risk of having increased medical care utilization in the following year. These results remained after removing mental health care utilization costs. CONCLUSIONS: In a population-based sample, depressive symptoms predicted greater medical care utilization, independent of a number of medical severity measures. Whether depressive symptoms are a risk marker or a causal risk factor for increased medical utilization remains to be explored.

Adolescent↗
PubMed2001

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.

Adult↗
PubMed2001

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.

Adolescent↗
PubMed2001

Capacity building for health promotion and chronic disease prevention--Nova Scotia's experience.

The purpose of this paper is to report on the capacity building efforts that took place during the dissemination research phase of Heart Health Nova Scotia (HHNS). HHNS, a health promotion research team, is funded by Health Canada and the Nova Scotia Department of Health. It is located in Halifax, Nova Scotia, a province of 937,000 people situated on the east coast of Canada. It has been a member of the Canadian Heart Health Initiative since its inception in 1989. The first phase of the program, Demonstration, was successfully completed in December 1995 (Heart Health Nova Scotia, 1995). In 1996, HHNS entered its second phase, Dissemination Research, which was conducted between April 1996 and March 2001 in the Western Health Region of Nova Scotia. This was completed in collaboration with organizations, community groups, and government agencies who joined HHNS to form the Heart Health Partnership (HHP) (Heart Health Nova Scotia, 2001). The main aim of this phase of the initiative was to build and research organizational capacity for health promotion and chronic disease prevention.

Diffusion of Innovation↗
PubMed1999

Trends in the prevalence and treatment of hypertension in Halifax County from 1985 to 1995.

BACKGROUND: The objective of this study was to document changes in the prevalence and treatment of hypertension in Halifax County from 1985 to 1995 in an effort to observe, at the population level, the consequences of the availability of new antihypertensive medications. METHODS: The study population comprised a random sample of Halifax County residents, aged 25-64 years, who responded to the 1985 and 1995 surveys of the Halifax County MONICA Project and residents who responded to the Nova Scotia Health Survey conducted in 1995. Data from the two 1995 surveys were pooled. Information on hypertension awareness and use of medication were obtained through questionnaires, and blood pressure was measured according to a standard protocol, using phase I and V of Korotkoff sounds as respective markers for systolic and diastolic pressures. Uncontrolled hypertension was defined as a systolic pressure of 140 mm Hg or greater and a diastolic pressure of 90 mm Hg or greater. Changes in the prevalence of hypertension, prescribing trends and medication costs were examined, and the association between the type of antihypertensive treatment and characteristics of the respondents with self-reported hypertension was investigated by multivariate logistic regression. RESULTS: Of the 917 people interviewed in 1985 and the 1338 in 1995, 274 (29.9%) and 356 (26.6%), respectively, reported a history of hypertension. When age was controlled for, the proportion of respondents reporting hypertension did not differ between survey years or between men and women. The proportion of treated respondents who had uncontrolled hypertension increased between 1985 and 1995, from 32.6% to 57.4% among men and from 38.0% to 42.6% among women. An increase was seen in the use of calcium-channel blockers (from 2.1% to 19.7%) and angiotensin-converting-enzyme inhibitors (from 5.2% to 25.4%); the proportion of patients receiving combination therapy or diuretics decreased (from 39.6% to 15.6% and from 31.3% to 17.2% respectively). These changes were associated with an increase in the average daily cost of medication from $0.48 to $0.85 per patient. INTERPRETATION: The shift to new antihypertensive drugs was not associated with improved blood pressure control, but it was associated with an increase in average medication costs per patient. Uncontrolled hypertension remains a public health problem.

Adult↗
PubMed1999

The prevalence of hyperlipidemia in women and its association with use of oral contraceptives, sex hormone replacement therapy and nonlipid coronary artery disease risk factors. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To report the prevalence of lipid and nonlipid coronary artery disease risk factors in women classified by use of oral contraceptives or sex hormone replacement therapy. DESIGN, SETTING AND PARTICIPANTS: A population-based cross-sectional survey in nine Canadian provinces (not including Nova Scotia) between 1988 and 1992 invited 13,506 women aged 18 to 74 years to participate. During a clinic visit after a home interview, a blood sample was obtained following a fast of 8 h or more from 8637 women. OUTCOME MEASURES: Fasting plasma total cholesterol, triglycerides, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, blood pressure, smoking status, self-reported diabetes, and self-reported use of oral contraceptive or sex hormone replacement therapy pills. MAIN RESULTS: The prevalence of oral contraceptive use was 41% for women 18 to 24 years old and 20% for women 25 to 34 years old. The prevalence of sex hormone replacement therapy was 4% for women 35 to 44 years old, 20% for women 45 to 64 years old and 11% for women 65 to 74 years old. Users of sex hormone replacement therapy aged 35 to 44 years had slightly higher mean LDL cholesterol than nonusers (3.04 versus 2.89 mmol/L). Users and nonusers aged 45 to 54 years had similar LDL cholesterol levels, and users aged 55 to 64 and 65 to 74 years had lower LDL cholesterol and higher HDL cholesterol levels, respectively, than nonusers. Triglyceride levels were higher in oral contraceptive users and in younger women on sex hormone replacement therapy than in nonusers. In the general population of Canada the use of oral contraceptives in women less than age 35 years had only a marginal effect on the prevalence of lipid and nonlipid risk factors. Women aged 18 to 24 years using oral contraceptives had a higher mean LDL cholesterol level of 2.73 versus 2.35 mmol/L for nonusers. The prevalence of lipid and nonlipid risk factors in women using sex hormone replacement therapy increased slightly for those aged 35 to 54 years and decreased in women aged 55 to 74 years. A lower percentage of women using sex hormone replacement therapy, aged 55 to 74 years, had high risk LDL cholesterol levels (21% versus 36% for nonusers). A larger percentage of women using sex hormone replacement therapy had low risk HDL cholesterol levels (54% versus 29% for nonusers). The nonlipid risk factor profile for women aged 35 to 54 years on sex hormone replacement therapy was less favourable than for nonusers: obesity was more common (36% versus 28%, respectively), hypertension was higher (22% versus 12%, respectively), and the proportion of women with one or more nonlipid risk factors was higher. The nonlipid risk factor profile for women 55 to 74 years of age who were using sex hormone replacement therapy was more favourable than for nonusers: obesity was lower (31% versus 47%, respectively), smoking was lower (7% versus 16%, respectively), sedentary behaviour was lower (28% versus 37%, respectively), and fewer women had two or more of these risk factors (31% versus 52%, respectively). CONCLUSION: The findings suggest that women at higher risk for coronary artery disease tend to have a lower prevalence of use of sex hormone replacement therapy.

Adolescent↗
PubMed1999

Prevalence of high plasma triglyceride combined with low HDL-C levels and its association with smoking, hypertension, obesity, diabetes, sedentariness and LDL-C levels in the Canadian population. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To report the associations of plasma triglyceride, high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) with nonlipid coronary artery disease risk factors. In particular, the associations for persons with high triglyceride and low HDL-C levels were examined. DESIGN: A stratified random probability sample of 29,855 men and women aged 18 to 74 years from the Canadian Heart Health Surveys (1986 to 1992) in 10 provinces. Blood samples were obtained from 18,555 participants who had fasted for 8 h or more. Plasma lipids were determined at the J Alick Little Lipid Research Laboratory, Toronto, Ontario, with standardization of the Centers for Disease Control Lipid Standardization Program, Atlanta. OUTCOME MEASURES: Fasting plasma total cholesterol, triglyceride, LDL-C and HDL-C levels. MAIN RESULTS: The prevalence of men with triglyceride levels above 1.7 mmol/L and HDL-C levels below 0.9 mmol/L was 10%, compared with 3% for men with triglyceride levels below 1.7 mmol/L and HDL-C levels below 0.9 mmol/L. The prevalence of women with triglyceride levels above 1.7 mmol/L and HDL-C levels below 0.9 mmol/L was 3% compared with a prevalence of less than 1% for women with triglyceride levels below 1.7 mmol/L and HDL-C levels below 0.9 mmol/L. Even when plasma LDL-C was low at less than 3.4 mmol/L, there was an age trend for increasing prevalences of the combination of triglyceride levels 2.3 mmol/L or greater and HDL-C levels less than 0.9 mmol/L in both sexes. The prevalence of a triglyceride levels 2.3 mmol/L or greater combined with an HDL-C level below 0.9 mmol/L was increased in groups who were cigarette smokers, diabetic, hypertensive, obese or sedentary, or who had higher LDL-C levels in both sexes, and the increase was even greater in the presence of two or more of these other risk factors. CONCLUSIONS: Among men or women with low HDL-C and high triglyceride levels, smoking, diabetes, sedentariness, hypertension and obesity were much more prevalent than among those at low risk with high HDL-C and low triglyceride levels.

Adolescent↗
PubMed1999

Plasma lipids and lipoprotein reference values, and the prevalence of dyslipoproteinemia in Canadian adults. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To report reference values for plasma lipids and lipoproteins in Canadian adults and the prevalence in the population of various levels of risk for coronary artery disease from dyslipoproteinemia. DESIGN, SETTING AND PARTICIPANTS: Population- based provincial heart health cross-sectional surveys in 10 provinces between 1986 and 1992 invited 29,855 men and women aged 18 to 74 years to participate. During a clinic visit after a home interview a blood sample was obtained following a fast of 8 h or more from 18,555 people. Plasma lipid levels were determined at the J Alick Little Lipid Research Laboratory, Toronto, with standardization of the Centers for Disease Control Lipid Standardization Program, Atlanta. OUTCOME MEASURES: Fasting plasma total cholesterol, triglyceride, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and non-HDL-C levels. MAIN RESULTS: Mean plasma total cholesterol, LDL-C, non-HDL-C and triglyceride levels increased with age in men to a peak at around age 54 years, while in women the increases were more gradual at a lower level until age 54 years, after which they increased appreciably eventually exceeding values for men. A high percentage of adults were at increased risk for coronary artery disease: 44% had elevated total cholesterol levels above 5.2 mmol/L; 14% had LDL-C levels above 4.1 mmol/L; 8% had HDL-C values below 0.9 mmol/L; and 14% had triglyceride levels above 2.3 mmol/L. Eleven per cent of adults had both total cholesterol level above 6.2 mmol/L and LDL-C level above 4.1 mmol/L. CONCLUSION: The high prevalence of Canadian adults at risk because of elevated plasma lipid levels strongly indicates the need for comprehensive public health programs to reduce plasma lipid levels in the population and the need to encourage physicians to treat those at high risk.

Adult↗
PubMed1999

Impact of different blood lipid evaluation and treatment guidelines on the proportion of Canadians identified and treated for elevated blood cholesterol. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To report on the impact of different blood lipid evaluation and treatment guidelines on the proportion of Canadians identified and treated for high blood cholesterol. DESIGN, SETTING AND PARTICIPANTS: The Canadian Heart Health Surveys were carried out in Canada between 1986 and 1991. The data used in this study were from cross-sectional probability samples of adults aged 18 to 74 years, gathered in four provincial health surveys (Quebec, Alberta, Manitoba and Ontario) between 1989 and 1992, which obtained information on family history of heart disease. Data reported are for 7238 subjects fasting 8 h or more and providing a blood sample. All blood lipid analysis were done at the J Alick Little Lipid Research Laboratory, University of Toronto, which is standardized according to the National Heart, Lung, and Blood Institute, Centers for Disease Control (Atlanta) Lipid Standardization Program. OUTCOME MEASURES: With respect to the four guidelines examined--the Canadian Consensus Conference on Cholesterol (CCCC), 1987; the Toronto Working Group on Cholesterol Policy (TWG), 1990; the Canadian Task Force on the Periodic Health Examination (PHE), 1993; and the National Cholesterol Education Program (NCEP), 1993, in the United States--a comparison of the proportion of individuals in the population for whom a lipid profile was constructed, and who were prescribed a diet and drug therapy under different assumptions of success with dietary therapy for each guideline. MAIN RESULTS: Major differences were observed in the impact of the various guidelines with respect to the percentage of subjects who were tested, provided with a lipid profile, and eligible for diet and/or drug therapy. In general the percentages in each group were higher for the CCCC and the NCEP guidelines than for the PHE and TWG guidelines. CONCLUSION: The divergent results obtained from the application of the various guidelines are cause for concern and explain in part the confusion that surrounds the topic of blood cholesterol in public health and clinical contexts. Public health policy in the area of cardiovascular disease prevention would benefit from explicit consideration of various types of criteria for formulation of identification and treatment guidelines.

Adolescent↗
PubMed1999

Prevalence of risk factors for cardiovascular disease in Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992.

BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.

Aged↗
PubMed1999

Knowledge and awareness of risk factors for cardiovascular disease among Canadians 55 to 74 years of age: results from the Canadian Heart Health Surveys, 1986-1992.

BACKGROUND: Cardiovascular disease is the leading cause of death and disability in older people, who account for an increasing proportion of Canada's population. Knowledge and awareness of risk factors is essential for changes in behaviour, yet little is known about these issues in older people. The Canadian Heart Health Surveys database provides a unique resource to examine knowledge and awareness of cardiovascular risk factors in older Canadians. METHODS: This descriptive cross-sectional study used data from the Canadian provinces' Heart Health Surveys, for the years 1986 to 1992. Sampling within each province consisted of stratified, 2-stage, replicated probability samples; 4976 people 55 to 74 years of age were included in the present analysis. Knowledge and awareness of cardiovascular risk factors was determined from the survey question "Can you tell me what are the major causes of heart disease or heart problems?" Blood pressure was measured during a home visit; anthropometric and blood measurements were obtained during a clinic visit. Cardiovascular health status was determined by self-reporting. RESULTS: Smoking and stress or worry were mentioned as major causes of heart disease by the greatest proportion of participants (41% and 44% respectively); hypertension was mentioned by only 16%. Men and women did not differ in their awareness of high blood cholesterol (cited by 23% of participants), smoking (41%), excess weight (30%) or lack of exercise (28%) as causes of heart disease. A greater proportion of women than men were aware of hypertension (19% v. 12%) and heredity (31% v. 17%) as major causes of heart disease. Awareness of risk factors was consistently lower in the older age group (65-74 v. 55-64 years). Among women, there was greater awareness of the respective risk factors as causes of heart disease among those who were smokers (60% v. 35% of nonsmokers), those who had a body mass index (BMI) of 25 or greater (38% v. 24% of those with a BMI less than 25) and those who were hypertensive (22% v. 17% of those without hypertension). Those who had experienced a heart attack had greater awareness of the major causes of heart disease than those who had not; this pattern was stronger among women than among men. Of those in whom elevated cholesterol level was identified during the course of the study, 62% of men and 67% of women were unaware of their cholesterol status. Of those in whom high blood pressure was diagnosed, 43% of men and 33% of women were unaware of their hypertensive status. INTERPRETATION: Awareness of the major causes of cardiovascular disease is low among older Canadians, especially among men and in those 65 to 74 years of age.

Aged↗
PubMed1998

Socioeconomic differences in the use of physician services in Nova Scotia.

OBJECTIVES: Socioeconomic differences in use of physician services in Nova Scotia, Canada were examined. METHODS: The study was based on survey data, containing information on socioeconomic status, linked to physician claims data. Socioeconomic differences in use of physician services were estimated, adjusted for age, sex, and region of residence. RESULTS: Large socioeconomic differences were observed in the use of physician services, with use inversely related to both household income and education. These differences remained after adjustment for age, sex, and region. CONCLUSIONS: Use of physician services is inversely associated with socioeconomic status.

Adolescent↗
PubMed1996

Coder gender and potential for hostility ratings.

This study examined the effects of coder gender on Potential for Hostility ratings. Six trained coders (3 men and 3 women) who were unaware of the coder gender effect hypothesis coded 30 male and 30 female undergraduates for Potential for Hostility. Although reliability estimates as calculated by Cronbach's alpha suggested that all coders were consistent, an analysis of variance revealed a significant main effect for coder gender, wherein female coders rated participants as displaying significantly less Potential for Hostility than did male coders. This significant difference was also meaningful, as coder gender accounted for 32% of the variance in Potential for Hostility scores. Thus, future Potential for Hostility investigations need to consider the gender of those coding, as this factor both significantly and substantially influences reported Potential for Hostility ratings.

Adult↗
PubMed1996

Effects of recruitment strategy on response rates and risk factor profile in two cardiovascular surveys.

BACKGROUND: The study was set up to assess the effect of recruitment methods on participation rate, response bias and cardiovascular risk factor estimates. METHODS: Two random samples of men and women in Halifax County aged 25-74 were drawn from the same sampling frame. Their respective sizes were 1007 (NSHHS) and 3036 (MONICA) people. Recruitment by Nova Scotia Heart Health Survey (NSHHS) was through face-to-face contact, whereas the MONICA survey relied on invitation by mail. Outcome measures were response rates at various stages of the recruitment process and the differences in cardiovascular risk factor estimates. RESULTS: Face-to-face recruitment located 51% and mail recruitment located 47% of their respective samples; face-to-face recruitment resulted in fewer individuals who refused to participate in the survey, but also produced fewer who were prepared to provide blood samples in addition to answering questionnaires. By-mail recruits were more likely to have post-secondary education, but did not differ in the proportion of smokers, mean diastolic blood pressure or body mass index, if controlled for education level, gender and age. However, the mean systolic blood pressure was 5.7 mmHg higher and the mean cholesterol level 0.44 mmol/l lower in face-to-face recruits. CONCLUSIONS: Controlling for age, gender and education level eliminates the effect of recruitment bias on most cardiovascular risk factors estimates. The exceptions in our study were systolic blood pressure and cholesterol, where methodological factors may have played a role.

Adult↗