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Biomedical subjects

J F Gentleman

Publications and source records attributed to J F Gentleman.

At least 19 recordsLinked to original sources
PubMed1999

Deaths due to dementia: An analysis of multiple-cause-of-death data.

This study analyzes multiple-cause-of-death information from over 113,000 death certificates of Canadians aged 65+ and identifies causes that are significantly likely and significantly unlikely to combine with dementia to cause death. For dementia as a mentioned cause and as the underlying cause of death, frequencies and rates of death were calculated. Dementia was mentioned on death certificates 2.4 times as often as it occurred as the underlying cause of death. Among the causes least associated with dementia were some cancers, chronic respiratory diseases and rheumatoid arthritis. Causes of death that rarely occur with dementia should be further investigated in terms of their potential role in preventing or delaying the onset of dementia. In particular, further study of the role of anti-inflammatory drugs and nicotine in reducing the risk of dementia is indicated. Causes positively associated with dementia largely reflect the physical deterioration it confers.

Age Distribution↗
PubMed1999

Mortality in metropolitan areas.

OBJECTIVES: This article examines differences in all causes mortality rates and rates for the leading causes of death (heart disease, cancer and cerebrovascular disease) by census metropolitan area (CMA). DATA SOURCE: The data are from the Canadian Vital Statistics Data Base maintained by Statistics Canada. ANALYTICAL TECHNIQUES: Annualized age-standardized mortality rates were calculated for Canada and for each CMA for the three-year period from 1994 to 1996. Differences between the CMA rates and the national rate were examined. MAIN RESULTS: Mortality rates tend to be high in CMAs in the Atlantic provinces and Québec and low in CMAs in the Prairies and British Columbia. Ontario contains CMAs with some of the highest mortality rates in Canada, as well as others whose rates are among the lowest. The pattern of mortality for specific causes also differs within CMAs: a CMA may have a high death rate for one cause, but a low rate for another.

British Columbia↗
PubMed1998

Falling short of Pap test guidelines.

OBJECTIVES: This article examines the associations between women's characteristics and getting or not getting a Pap test. DATA SOURCE: The data are from the 1994/95 National Population Health Survey (NPHS) conducted by Statistics Canada. ANALYTICAL TECHNIQUES: Multivariate logistic regressions were used to determine the odds of women not complying with Pap test guidelines, that is, of never having had a Pap test, and among women who had had one, of not having done so in the last three years. MAIN RESULTS: One in four women aged 18 to 69 had either never had a Pap test or had not had one in the three years before the NPHS. Notably, older women--who are at the greatest risk for cervical cancer--are less compliant with screening guidelines than younger women. Other characteristics of women with high odds of never having had a Pap test are: being single, being a resident of Quebec, having immigrated to Canada, having less than a secondary school education, not being in the highest income group and having had no sex partners in the previous year.

Adult↗
PubMed1997

Health and gender differences between middle and senior managers in the Canadian Public Service.

Most studies of the relationship between socioeconomic status (SES) and health have concentrated on disparities between the richest and poorest men; few studies have examined such relationships for women due to difficulties in measuring SES for women. For the present study, data collected from Canadian Public Service middle and senior managers provided an opportunity to examine associations between SES and health within the upper end of the SES spectrum for both genders, since women managers can be assumed to have a relatively high SES. Demographic, health and lifestyle characteristics are compared for middle and senior managers for each gender separately to determine whether women experience the health benefits associated with higher SES that have been previously observed for men. The results support the hypothesis that achieving a higher SES through work is a more stressful process for women than for men and that women's upward mobility is restricted compared to that of men. Despite these findings, there is little evidence that women's health has been adversely affected. Compared to male managers, fewer female managers smoke or drink and fewer have high body mass index, high blood pressure or high cholesterol levels. Female managers are also more likely to report being in good health.

Administrative Personnel↗
PubMed1996

Surgical rates in subprovincial areas across Canada: rankings of 39 procedures in order of variation.

OBJECTIVE: To rank 39 surgical procedures in order of variation of inpatient surgical rates, according to a new index of variation and to test the hypothesis that there is greater variation for primarily discretionary operations than for primarily non-discretionary operations. DESIGN: A population-based retrospective cohort study. SETTING: Nine provinces (99.19% of Canada's population). PARTICIPANTS: All hospital inpatients who underwent any of 39 types of surgery and were separated from hospital between Apr. 1, 1988 and Mar. 31, 1990 (the most recent time period for which Canada-wide data were available at the subprovincial level analysed). MAIN OUTCOME MEASURE: Rankings of the 39 procedures according to the index of variation, calculated from inpatient surgery rates in 255 census divisions across Canada. RESULTS: The 13 procedures with the greatest variation were all primarily discretionary. Thirteen of the 14 procedures with the lowest variation were primarily non-discretionary. All but one of the procedures whose degree of discretion was deemed intermediate were in the middle third of the rankings. CONCLUSIONS: The greatest variation is found in primarily discretionary operations. Further investigation should be focused on identified geographical locations where rates for operations that are primarily discretionary are unusually high or low, and particularly on those operations for which there is disagreement regarding the indications for surgery.

Canada↗
PubMed1995

The impact of estimation method and population adjustment on Canadian life table estimates.

Abridged life tables centred on 1991 were produced from the 1991 Canadian census, net census undercoverage estimates, and death data from 1990 to 1992. The sensitivity of life table values to differing methods of estimation and population estimates was investigated. The results from four methods by Greville, Chiang, and Keyfitz were compared, and population estimates, both adjusted and unadjusted for net census undercoverage, were used to test the effects of method and type of population estimates on life table values. The results indicate that the method used to derive the estimates had much less influence on the life table values than did the choice of population estimate. The change in life expectancy at birth due to the method of calculation chosen was at most 15 days, whereas the change due to the population estimate chosen was about 73 days. Since there are age, sex and provincial variations in net undercoverage rates, life expectancies differed accordingly.

Adolescent↗
PubMed1994

High and low surgical procedure rates in census divisions across Canada.

This paper identifies outliers (unusually high or low values) among rates of 39 surgical procedures in 255 Canadian census divisions. Surgery rates for the two-year period from April 1988 through March 1990 were standardized for age and sex, and then "normalized" to adjust for differences in census division population sizes. Among the 39 procedures, a total of 402 outlying census division rates were found, of which 48 were deemed to be very high, 254 high, 79 low, and 21 very low. The results are presented for individual procedures, by province, and for the 16 census divisions in which medical schools and their associated teaching hospitals are located.

Adolescent↗
PubMed1994

Age differences of married and divorcing couples.

This paper analyzes the probability of a married couple getting divorced, based on the age difference between the husband and wife. To calculate such probabilities, the distribution of age differences of married couples was derived from the 1991 Census and the 1990 General Social Survey, and the distribution of age differences of divorcing couples was obtained from 1991 divorce data provided by the Department of Justice Canada. These distributions, the first based on data that are seldom available, are also analyzed in this paper. The results provide details about the expected significant imbalances that exist, both for married and divorcing couples, between the number of couples with older husbands and the number with older wives. A model is developed that shows that divorce rates are lowest when the husband is two to ten years older than the wife or when the magnitude of their age difference is extremely large. Furthermore, the chance of divorce is much higher when the wife is older than the husband than vice versa. The demands on a younger spouse--usually the wife--to provide informal health care for an older spouse are briefly discussed.

Adolescent↗
PubMed1993

Career earnings and death: a longitudinal analysis of older Canadian men.

There is widespread interest in disparities in health status across income groups and other classifications of socioeconomic status. In Canada, as in many other countries, there is considerable evidence showing such disparities. This study reports an analysis of male mortality at ages 65 to 74 in relation to socioeconomic characteristics, specifically employment and self-employment earnings histories during the 10 to 20 years prior to age 65, marital status, disability, and age at retirement. The analysis is based on administrative data from the Canada Pension Plan covering more than 500,000 individuals. Significant mortality gradients are found throughout the earnings spectrum. These gradients are also clearly evident in a multivariate context. The results illustrate the major potential of administrative data for research. Substantively, the results cast doubt on the primacy of causal explanations such as "reverse causality" and "health selection" and raise important questions regarding pension and health policy.

Aged↗
PubMed1993

Risk factors for hypertension as measured by the Canada Health Survey.

This paper examines the association between hypertension and demographic, genetic, personal, and socio-economic risk factors. Logistic regression models were fitted to data from the 1978-79 Canada Health Survey. The analysis showed that age, sex, genetic history, and body mass index were important factors in predicting high blood pressure. For males, blood cholesterol and exercise were other contributing factors; for females, hypertension also had significant associations with marital status, geographical region, and economic family income.

Adolescent↗
PubMed1992

The development of staging data for use in the microsimulation of lung cancer.

Lung cancer incidence rates by cell type and stage were required for a lung cancer microstimulation submodel developed at Statistics Canada. Lung cancer incidence rates not disaggregated by stage were calculated for different histological cell types using Canada's National Cancer Incidence Reporting System data. In the absence of national lung cancer staging information, staging data from the province of Alberta were collected and rates of occurrence were calculated for different stages of lung cancer at time of diagnosis. Imputation procedures were used to maximize the amount of usable staging data. The Alberta stage rates were combined with the Canadian incidence rates to obtain estimates needed by the microsimulation submodel of the annual probability of an individual of a particular sex and age being diagnosed with lung cancer of each cell type at each stage. This project, although highly specialized, illustrates the need for more extensive and standardized staging data for cancer in Canada.

Adolescent↗
PubMed1992

The consistency of various high blood pressure indicators based on questionnaire and physical measures data from the Canada Health Survey.

Several indicators of the presence of high blood pressure, taken from different parts of Canada Health Survey data, are compared at the individual respondent level to determine their consistency and their usefulness, alone or in combination, in measuring the prevalence of hypertension. The results demonstrate some systematic and substantial discrepancies among various high blood pressure indicators derived from questionnaire data, and between questionnaire data and physically measured blood pressure status.

Adolescent↗
PubMed1991

An analysis of frequencies of surgical procedures in Canada.

This paper reports preliminary and selected results of an analysis of the frequencies of 36 common surgical procedures in hospitals across Canada during the period April 1985 to March 1987. Age-sex-specific and age-sex-standardized procedure rates were calculated for each procedure for each of 245 Census Divisions (CDs) across Canada, as well as for 338 smaller urban areas (FSAs) within the province of Ontario. Special attention was given to adjusting the rates for differing population sizes of the geographical regions. Procedure rates were computed based on the residence of the patient, not on the location of the hospital. Graphical techniques, analysis of variance, and other statistical techniques were used to identify unusually high or low procedure rates and to determine effects due to differences in age, sex, and geographical region. The relationship of procedure rate to the socio-economic level of a region (as measured by the proportion of low-income individuals in the region) was analyzed.

Canada↗
PubMed1989

The distribution of the frequency of occurrence of nucleotide subsequences, based on their overlap capability.

DNA's genetic code can be represented as an alphabetic sequence composed of the four letters A, C, G, and T, which represent the four types of nucleotides--adenylic, cytidylic, guanylic, and thymidylic acid--of which DNA is composed. Now that these sequences have been identified for many genes and are available in computer-readable form, scientists can analyze these data and search for patterns in an attempt to learn more about the regulatory functions of the gene. One area of study is that of the frequency of occurrence of specific nucleotide subsequences (e.g., ACAC) within part or all of a nucleotide sequence. This paper derives the probability distribution of the frequency of occurrence of a subsequence within a nucleotide sequence, under the hypothesis that the four nucleotides occur at random and with equal probability. This distribution is nontrivial because different subsequences have different "overlap capability." For example, the subsequence AAAA can occur up to 17 times in a sequence of length 20 (which would happen if the sequence were composed solely of A's), but the subsequence ACGT cannot occur more than 5 times in a sequence of length 20. Thus, the frequency distributions are different for each type of overlap capability. It is of interest to assess and compare the degree of nonrandomness for different subsequences or among different portions of a sequence; the existence and degree of nonrandomness may be related to the type and degree of functionality of a nucleotide (sub)sequence. The frequency distributions provided here can be used to perform exact significance tests of the hypothesis of randomness. An approximate test is also described for use with long sequences; this can be used to test a more general null hypothesis of nucleotides occurring with unequal probabilities.

Algorithms↗