Search PubMed⌕ Search

Biomedical subjects

W J Millar

Publications and source records attributed to W J Millar.

At least 37 records · Page 2Linked to original sources
PubMed1996

Pregnancy outcomes.

Live births, induced abortions, and miscarriages/stillbirths are usually examined separately. This article combines the three outcomes to focus on pregnancy in Canada from 1974 to 1992. An estimated 525,100 pregnancies ended in Canada during 1992. While this was a substantial increase from 438,300 in 1974, the pregnancy rate in 1992-77 pregnancies per 1,000 women aged 15 to 44-was actually lower than in 1974, when it had been 85 per 1,000. As the pregnancy rate declined, there was a shift in outcomes. The share of pregnancies that ended in live births fell from 79% to 76%, and the proportion ending in miscarriages/stillbirths went from 9% to 5%. A growing proportion of pregnancies ended in abortions: 19% in 1992, compared with 12% in 1974. Trends in pregnancies varied with the age of the women. Pregnancy rates rose among those in their thirties, but dropped at all other ages. Consequently, older women accounted for a larger share of pregnancies at the end of the period than they had at the beginning. Pregnancy outcomes also differed depending on the women's age. The proportion that ended in an abortion was relatively high among women under age 25 and age 40 and over. Throughout the 1974-1992 period, the proportion of pregnancies ending in miscarriages or stillbirths fell among women of all ages.

Abortion, Induced↗
PubMed1996

Declining cesarean section rates: a continuing trend?

Since the mid-1980s, cesarean section rates in Canada have declined. By 1993, 18 of every 100 deliveries were by cesarean section, compared with close to 20 per 100 in 1987. As well, in 1993, 9 of every 100 deliveries were primary cesareans, down from a high of almost 11 per 100 in the mid-1980s. And the repeat cesarean section rate fell from 39 per 100 cesareans in the mid-1980s to 34 in 1993. A major factor in the downtum of cesarean section rates has been a steady increase in vaginal births after cesarean section (VBACs). From 1979 to 1993, the rate rose more than tenfold from 3 to 33 per 100 women who previously had a cesarean section. This trend toward VBAC deliveries was apparent among women in all age groups. Within Canada, there are large provincial differences in cesarean section and VBAC rates. In 1993, cesarean rates ranged from 15 per 100 deliveries in Manitoba to 22 in New Brunswick. VBAC rates ranged from 16 per 100 previous cesarean sections in New Brunswick and Newfoundland to 42 in Alberta. This article traces trends in cesarean section and VBAC rates in Canada and the provinces from 1979 to 1993. The data are based on individual patient admission/separation records of general and allied hospitals, that are submitted to Statistics Canada.

Adult↗
PubMed1996

Selective screening for abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) meets the criteria as a possible target for early detection by screening or case-finding, although the effectiveness of such an intervention has not yet been demonstrated. The purpose of this study was to estimate the increase in cost-effectiveness that would result from selectively screening individuals based on their risk of AAA. Data from a hospital-based case-control study involving 78 men with AAA (unruptured) and 99 male controls were used to derive a risk function based on age, cigarette smoking, high blood pressure, history of heart disease, body mass index and serum high-density lipoprotein, using logistic regression analysis. For each of the control subjects (assumed to be a representative sample of the general population of elderly men), the risk of AAA was estimated and multiplied by the expectation of life to give a measure of the potential benefit of screening. The proportion of the total potential benefit that would be obtained by screening only those with a given level of risk was estimated, and this was related to the proportion of the population screened. In order to obtain 80% of the total potential benefit among men, we found that it would be necessary to examine 52% of the elderly male population if using a risk function based on age alone; 35% would have to be screened if age and smoking were included; and 17% would require screening if all the risk factors were included. Selective screening for AAA appears to be a promising strategy, but a prospective study is required to demonstrate that the predictions are valid.

Aged↗
PubMed1996

Reaching smokers with lower educational attainment.

Between 1977 and 1994, smoking rates declined among men and women, but the decline was steeper for men. While smoking rates fell among people at all levels of education, the smallest drop was among those with high school graduation or less, particularly women. For those who had stopped smoking, health concerns had been the overriding factor. Smokers with lower education reported encountering fewer smoking restrictions in their daily activities than did those with higher education. All smokers cited the mass media as their major source of information about smoking, but those with lower education reported the mass media less often than did smokers with higher levels of attainment, and were less likely to obtain information from books, pamphlets or magazines. In addition, smaller percentages of smokers with lower education recalled printed warnings about heart disease on cigarette packages. Variations in the decline of smoking suggest that health promotion and smoking cessation programs should consider sex and educational differences when targeting the smoking population. Differences in rates of smoking among people aged 20 and over were examined by educational attainment using selected health surveys conducted between 1977 and 1994. A Health Canada-sponsored supplement to Statistics Canada's National Population Health Survey was used for data on other aspects of smoking such as cutting back or attempting to quit, sources of health information, and awareness of smoking restrictions and cigarette package warnings.

Adult↗
PubMed1995

Trends in mortality and hospital morbidity due to abdominal aortic aneurysms.

This article examines national and regional trends in mortality and morbidity due to abdominal aortic aneurysms from 1969 to 1991. Annual age-adjusted mortality and hospital separation rates were calculated for men and women aged 55 and older whose underlying cause of death was abdominal aortic aneurysm, or who were hospitalized with a primary diagnosis of abdominal aortic aneurysm. In recent decades, abdominal aortic aneurysm mortality rates remained stable, in contrast to substantial declines in mortality rates for cerebrovascular disease and cardiovascular disease. The pattern was similar for both sexes, although rates were four to five times higher among men than among women. In 1991, age-adjusted rates were around 31.0 per 100,000 men aged 55 and over and 8.5 per 100,000 women aged 55 and over. Over the 1969 to 1991 period, mortality rates in all regions tended to converge. Although mortality rates were stable, hospital separation rates for abdominal aortic aneurysms increased sharply, particularly for unruptured aneurysms. Screening programs have been able to detect asymptomatic abdominal aortic aneurysms, and surgical intervention can substantially reduce mortality. However, the costs and benefits of screening programs should be assessed. If current mortality rates persist, as the baby boom ages there will be an absolute increase in the number of deaths from abdominal aortic aneurysms.

Age Distribution↗
PubMed1995

The elimination of disease: a mixed blessing.

The increase in life expectancy that would result from the elimination of certain diseases and the resulting change in hospital utilization vary, depending on the disease. In some cases, life expectancy would rise and total days spent in hospital would decline, while in others, the gain in life expectancy would be accompanied by an increase in hospital days. For instance, if mental health disorders were eliminated, the increase in life expectancy at age 45 would be minimal: from 34.9 to 35.3 years, but time spent in hospital would decline from 168 to 151 days. By contrast, if diseases of the circulatory system were eliminated, life expectancy at age 45 would rise from 34.9 to 41.6 years, but time spent in hospital would also rise: from 168 to 209 days. Elimination of not only mental illnesses but also injuries and poisoning and diseases of the nervous system has the potential of both increasing life expectancy and reducing hospital use.

Aged↗
PubMed1995

Accidents in Canada, 1988 and 1993.

Using data from Statistics Canada's 1988 and 1993 General Social Survey (GSS), this article examines the incidence and consequences of accidents in Canada and the characteristics of respondents aged 15 and over who were involved in them. In 1993, an estimated 3.9 million Canadians reported that they had been involved in 4.8 million accidents in the previous 12 months. Motor vehicle accidents and sports accidents were the most frequent, each accounting for about 27% of incidents, followed by accidents at work (21%) and at home (14%). Accidents were most common among young people, particularly men. However, from 1988 to 1993, there was a decline in the proportion of adults reporting accidents, and the sharpest drop was for the age group most at risk-15- to 24-year-olds. Most of the downturn was attributable to a decrease in the motor vehicle accident rate. Since alcohol is known to be associated with accidents, reduced consumption during the same period may have been partly responsible for the decline in accident rates. Other factors that may have contributed include stricter enforcement of impaired driving legislation and speed limits, and improvements in automobile safety. Nonetheless, despite the decline in accident rates, the toll taken by accidents reported in 1993 was considerable: 80% of accidents caused personal injury, and almost half of these resulted in medical attention in a hospital. Overall, 62% of accidents resulted in activity-loss days, and 29% involved bed-disability days. Hospital utilization costs associated with these accidents in 1993 were about $1.5 billion. As well, about one-third of accidents involved out-of-pocket expenses, totalling $791 million. Moreover, accidents continue to be the leading cause of death among persons under age 44.

Absenteeism↗
PubMed1994

Hip fractures: mortality, morbidity and surgical treatment.

Fracture of the neck of the femur (or hip fracture) is an important cause of mortality and morbidity among the elderly, and contributes significantly to health care costs. This paper examines recent Canadian trends in mortality and hospital morbidity attributable to this condition. Age-standardized rates for deaths, hospital admissions and hospital days at ages 55 and over are presented, and average annual percentage changes are estimated for each of these statistics using logarithmic regression. Changing trends in surgical procedures used to treat femoral fractures are also examined and linked with mean lengths of hospital stays. Between 1972 and 1990, deaths due to femoral fractures declined an average 2.3% annually for women and 1.2% for men. Hospital admissions dropped 0.1% for women and remained stable for men, while hospital days fell by 2.9% and 1.9% respectively. Beginning in 1977 there was a marked reduction in the proportion of admissions due to femoral fractures for which no surgical intervention was recorded and a corresponding increase in the proportion of fractures treated surgically by open reduction. Changes over the past two decades in the surgical treatment of patients with fracture of the neck of the femur may have reduced the hospital care burden. It is not possible from the available data to determine whether changes in treatment have also contributed to the observed reduction in mortality due to hip fracture. Neither can this downward trend be attributed to a fall in the condition's incidence, given observed hospital admission rates. Programs to prevent osteoporosis, falls, and injuries from falls are needed to complement improvements in surgical procedures.

Accidental Falls↗
PubMed1994

Second trimester abortions: trends and medical complications.

As a proportion of total abortions, those performed in the second trimester declined from 21% in 1974 to 10% in 1991. Second trimester (13 to 24 weeks) abortions were more frequent among women who were single, under age 20, and without prior deliveries or abortions. The stage of pregnancy at which an abortion was performed and the method used were associated with the risk of medical complications. Complication rates increased directly with the period of gestation. The complication rate for second trimester abortions was 13 times higher than that of first trimester abortions (under 13 weeks). The lowest complication rates were found among abortions performed using surgical D&C and suction D&C. The procedures primarily used for abortions at 16 or more weeks' gestation (i.e. the administration of prostaglandin, urea or saline) were associated with higher complication rates.

Abortion, Legal↗
PubMed1993

Prevalence of and risk factors for sudden infant death syndrome in Canada.

OBJECTIVE: To analyse and describe the prevalence of sudden infant death syndrome (SIDS) in the Canadian population in relation to the distribution of known risk factors for the syndrome. To explain the observed interprovincial variation in SIDS rates. DESIGN: Retrospective population-based case-control study. SETTING: All the provinces and territories of Canada except Quebec. SUBJECTS: The birth and infant death records of singleton births for 1986-88 were linked. The linkage was successful in matching 904 (86%) of the 1053 deaths attributed to SIDS to the birth file for the infant. For each SIDS case three control babies who survived infancy were chosen at random, matched by province of birth. MAIN OUTCOME MEASURES: Infant death classified as a "sudden infant death." Independent variables included infant's sex, birth weight and gestational age, being small for gestational age, mother's age, marital status and parity, and father's age. RESULTS: The risk of SIDS was greater for boys (odds ratio [OR] 1.47, 95% confidence limits [CLs] 1.26 and 1.70) than for girls and was greater for the infants of unmarried women (OR 3.48, 95% CLs 2.94 and 4.11) than for those of married women. The risk of SIDS was inversely related to birth weight (p < 0.001), duration of pregnancy (p < 0.001) and mother's age (up to age 35) (p < 0.001) and was directly related to parity (up to four) (p < 0.001). The available information on birth and death registrations enabled about 30% of deaths from SIDS to be predicted. CONCLUSIONS: Logistic regression equations based on the risk factors available in vital statistics data have low power to predict provincial differences in rates of SIDS. Consequently, there may be additional factors that may explain provincial variation. There is a need for a well-designed case-control study that examines more variables than are available through vital registration systems.

Canada↗
PubMed1993

Social status and health risks in Canadian adults: 1985 and 1991.

Smoking, overweight and physical inactivity are three lifestyle risk factors associated with increased risks of cancer, heart disease and other chronic diseases. Using data from the 1985 and 1991 General Social Surveys, this study examines the prevalence of these risk factors by respondents' education levels, and how the prevalence of these risk factors changed from 1985 to 1991. The prevalence of smoking, overweight and physical inactivity varied widely by respondent's education levels. In 1991, persons with more education had consistently lower rates for all three risk factors than those with lower educational levels. Smoking and sedentary living declined between 1985 and 1991, but the prevalence of overweight increased. However, except for physical activity, little progress was made in narrowing the socio-economic differences for these risks. Declines in the prevalence of health risks varied by educational level and by sex within educational level. This has implications for future patterns of chronic disease morbidity and mortality. Differences in risk factor prevalence between socioeconomic groups may be partly due to differences in how each group acquires and interprets health information, and to differences between groups' exposure to environments that support healthy lifestyles.

Adult↗
PubMed1992

Place of birth and ethnic status: factors associated with smoking prevalence among Canadians.

The prevalence of smoking is lower among foreign-born (16%) than among native-born Canadians (25%). In addition, foreign-born smokers smoke fewer cigarettes a day than the native-born. Foreign-born Canadians also tend to smoke cigarettes with a lower tar yield. The differences in the smoking behaviour of foreign-born and native-born Canadians suggest that the foreign-born may be at lower risk from smoking related morbidity and mortality. National smoking rates conceal wide variations in smoking prevalence by ethnic group. The highest smoking rates in Canada are found among Canadian Aboriginals. About 59% of Aboriginal Canadians smoke on a regular basis. In contrast, only 11% of Asian Canadians smoke regularly. These marked differences in smoking rates among ethnic groups are an argument for addressing the unique behaviour of each ethnic group within existing health promotion programs. Four out of ten smokers (42%) attempts to quit smoking during the course of a year. This percentage does not vary much by gender or by foreign-born/native-born status. The high percentage of smokers who attempt to quit during a year probably reflects the combined impacts of smoking prevention programs, increased taxation on cigarettes, and smoking restrictions on smoking in the workplace and in public settings.

Adolescent↗
PubMed1992

Multiple births: trends and patterns in Canada, 1974-1990.

This paper examines Canadian trends and patterns in multiple births in relation to total confinements, singleton births, maternal age, parity, gestational age and birth weight using vital statistics from 1974 to 1990. Multiple-birth rates in Canada increased from 912.8 to 1,058.9 per 100,000 confinements between 1974 and 1990. The increase is especially noticeable for women over 30. The rate of triplet and higher-order births increased from 8.3 to 21.7 per 100,000 confinements between 1974 and 1990. The proportion of multiple-birth babies that were pre-term (< 37 weeks gestation period) increased from 32.8% in 1974 to 45.8% in 1990. Factors associated with the increase in multiple births may include the use of assisted pregnancy techniques, and the fact that women aged 30 and older, who are at higher risk of a multiple birth, and who postponed their child bearing, have increased their fertility. The sharp increase in multiple-birth rates has implications for maternal and child health and health care costs.

Adolescent↗
PubMed1991

Trends in low birthweight Canada. 1971 to 1989.

This paper reviews the levels of and the trends in low birthweight (under 2,500 grams) and premature births (less than 37 weeks gestation) in Canada from 1971 to 1989. Low birthweight (LBW) characterized 6.6% of births in 1971 and 4.6% of births in 1989: this represents a decline of 30% in LBW for the period. The decline was evident for mothers in all age groups, and for all birth parities. However, the prevalence of very low birthweights (less than 1,500 g) remained stable during the period, accounting for 0.8% of births in 1971 and 0.7% in 1989. Preterm births (less than 37 weeks of gestation) increased from 47% of all LBW births in 1971 to 60% in 1989. This shift and the small decline in the prevalence of preterm LBW babies has clinical and preventive implications. These and other findings are based on analysis of 6.6 million single live births between 1971 and 1989.

Adult↗
PubMed1991

Patterns and change in Canadian fertility 1971-1988: first births after age 30.

An analysis of Canada's changing pattern of births during the period 1971-1988 suggests that the tempo and timing of fertility has changed. Between 1971 and 1988, the number and rates of first births to women in their 30s increased rapidly, and rates for women younger than 25 declined. The rate of first births (first births per 1,000 women) for women 30-34 increased from 11.5 in 1971 to 17.1 in 1981 and to 22.3 in 1988--a 94% increase over the 17 years. The rate for women 35-39 also rose from 3.0 in 1971 to 3.6 in 1981 and 5.9 in 1988--a 97% increase occurring mostly in the 1980s.

Adolescent↗
PubMed1990

Smoking prevalence in the Canadian Arctic.

Two recent surveys of adults and of children in the Canadian Arctic obtained information on smoking behaviour. By age nineteen, 71% of Inuit youth were current smokers compared to 63% of Dene/Métis youth and 43% of the Non-Native. Within each ethnic group, the general pattern of higher smoking rates among girls in almost all age groups was apparent. Inuit girls age 15-19 had the highest smoking rates. Seventy seven percent reported that they were current cigarette smokers. Of all adolescent regular smokers, about 12% smoked more than 15 cigarettes per day. However, among Non-Native youth the percentage increased to 23%. Among both boys and girls, the frequency of smoking was highest among Non-Native youth, intermediate among Dene/Métis youth and lowest among the Inuit. In each ethnic group boys were more likely than girls to smoke over 15 cigarettes per day. Adult smoking rates in the Arctic were higher than rates in the national population. Inuit adults had the highest smoking rates, followed by the Dene and the Non-Native groups. Men and women in each of the ethnic groups in the Northwest Territories had higher smoking rates than their counterparts in the national population.

Adolescent↗