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Biomedical subjects

Y Mao

Publications and source records attributed to Y Mao.

At least 289 records · Page 16Linked to original sources
PubMed1989

Dynamic analysis of organic acids in extracellular fluids of human dental plaques.

Organic acids in unstimulated saliva and extracellular fluids of dental plaques from 12 middle school students were measured by ion-chromatography. The acids in the plaques were analyzed before and 5-10, 30-35, 60-65 minutes after rinsing with 10% sucrose solution. The differences of the acids between the extracellular fluids of resting plaques and unstimulated saliva were significant. In the extracellular fluids of plaques, the concentration of high pK acids, i.e. acetic and propionic acids was higher than that of low pK acids i.e., lactic and formic acids before and after sucrose rinse. The relations of time-dependent changes between the ratio of low pK to high pK acids and pH were observed in the extracellular fluids of plaques after sucrose rinse. No significant difference of lactic acid concentrations was found between the caries-active and caries-free subjects 30-35 minutes after sugar rinse. The concentration of acetic acid was much higher in the extracellular fluids of dental plaque at any time. It is suggested that there may be some relationship between acetic acid and caries process.

Acetates↗
PubMed1988

Survival rates among patients with cancer in Alberta in 1974-78.

We calculated 5-year crude and relative survival rates, by age and sex, for patients in Alberta in whom cancer was diagnosed between 1974 and 1978. Cancers with low overall 5-year relative survival rates (less than 35%) included stomach cancer, cancer of the pancreas, lung cancer, brain cancer, multiple myeloma and myeloid leukemia. Cancers with high overall 5-year relative survival rates (more than 70%) included melanoma, breast cancer, cancer of the uterus, cancer of the bladder and Hodgkin's disease. Five-year relative survival rates were generally lower in the highest age group (75 years or more). A strong inverse relation between age and survival was noted for brain cancer, non-Hodgkin's lymphoma, Hodgkin's disease and myeloid leukemia.

Adult↗
PubMed1988

Risk factors for hypertension: results from a cross-sectional survey.

A case-control study of hypertension was conducted, using as a sampling frame a cross-sectional survey of Canadian Federal civil servants. Three case groups were selected, based on prior knowledge of hypertensive status and measured blood pressure. A 3-to-1 matching scheme was employed. Data was analysed using a logistic regression model. Statistically significantly elevated odds ratios, in excess of 3.0, were noted for overweight or obese status. Other odds ratios associated with a significantly increased risk of hypertension were maternal and paternal history of hypertension and current cigarette smoking.

Adult↗
PubMed1988

Major risk factors for cardiovascular disease mortality in adults: results from the Nutrition Canada Survey cohort.

The cardiovascular mortality experience of over 7000 Canadians ages 35-79 years free of self-reported heart disease or stroke who participated in the Nutrition Canada survey is presented. The effects of various risk factors on cardiovascular disease mortality were assessed using multivariate Poisson regression analyses. Factors associated with a significantly increased risk of dying included cigarette smoking, hypertension, diabetes and, for women, serum cholesterol. Relative risks were similar for those ages 35-64 years compared to those 65-79 years for diabetes but were higher among those 35-64 years for cigarette smoking, diastolic hypertension, obesity and serum cholesterol (females only). Individuals drinking three or more drinks daily had a relative risk of 3.18 for stroke. Population attributable risks for smoking, hypertension, elevated serum cholesterol and diabetes, respectively, were 47%, 21%, 7% and 8% for men and 10%, 21% 18% and 16% for women.

Adult↗
PubMed1988

Cancer mortality among a group of fluorspar miners exposed to radon progeny.

A cohort study of the mortality experience (1950-1984) of 1,772 Newfoundland underground fluorspar miners occupationally exposed to high levels of radon daughters (mean dose = 382.8 working levels months) has been conducted. Observed numbers of cancers of the lung, salivary gland, and buccal cavity and pharynx were significantly elevated among these miners. A highly significant relation was noted between radon daughter exposure and risk of dying of lung cancer; the small numbers of salivary gland (n = 2) and buccal cavity and pharynx (n = 6) cancers precluded meaningful analysis of dose response. Attributable and relative risk coefficients for lung cancer were estimated as 6.3 deaths per working level month per million person-years and 0.9% per working level month, respectively. Relative risk coefficients were highest for those first exposed before age 20 years. Cigarette smokers had relative and attributable risk coefficients comparable to those of nonsmokers. Relative risks fell sharply with age, whereas attributable risks were lowest in the youngest and oldest age groups. The results suggest that efforts to raise existing occupational exposure standards may be inappropriate.

Epidemiologic Methods↗
PubMed1988

Cardiovascular disease mortality trends and related risk factors in Canada.

Large declines have occurred in cardiovascular disease mortality in both sexes in Canada during the past two decades. However, there are many countries with substantially lower rates at the present time. Ischemic heart disease mortality accounts for about 60% of cardiovascular disease mortality. Cardiovascular disease rates have declined progressively since the mid-1960s in males 35 to 64 and 65 or more years of age, as well as in females in the latter age group. In younger females, 35 to 64 years of age, a slowly progressive reduction in rates started as early as 1930. Trends for stroke mortality also reveal similar long term reductions in rates since 1930 in both sexes. Relative risks for smoking, hypertension, elevated serum cholesterol and diabetes were analyzed. Almost one-third of the cardiovascular deaths in males were attributable to smoking. Population attributable risks for the four risk factors together were 53% for both sexes. Attention is drawn to the increased risks for persons in lower socioeconomic groups and those with low standards of education and the importance of recognition of these factors in intervention programs.

Adult↗
PubMed1987

Increased rates of illness and death from asthma in Canada.

Recent rates of illness and death from asthma in Canada and rates of hospital admission/separation for asthma were examined by age group and region. The death rates were higher in 1982-84 than in 1970-72, especially among those aged 15 to 34 years. Increases were also noted in hospital admission/separation rates, especially among those less than 15 years of age. Hospital admission/separation rates were highest in the Maritime provinces and Saskatchewan, whereas death rates were highest in Alberta and Saskatchewan. Examination of death certificates for coding errors and recoding of certificates to a single (8th) revision of the International Classification of Diseases indicated that changes in disease coding and errors in coding did not account for the significant increase in rates of death from asthma for those aged 15 to 34 years. These increases in rates of illness and death from asthma are unexplained and warrant further investigation.

Adolescent↗
PubMed1987

Deaths in Canada from lung cancer due to involuntary smoking.

Recently published evidence indicates that involuntary smoking causes an increased risk of lung cancer among nonsmokers. Information was compiled on the proportion of people who had never smoked among victims of lung cancer, the risk of lung cancer for nonsmokers married to smokers and the prevalence of such exposure. On the basis of these data we estimate that 50 to 60 of the deaths from lung cancer in Canada in 1985 among people who had never smoked were caused by spousal smoking; about 90% occurred in women. The total number of deaths from lung cancer attributable to exposure to tobacco smoke from spouses and other sources (mainly the workplace) was derived by applying estimated age- and sex-specific rates of death from lung cancer attributable to such exposure to the population of Canadians who have never smoked; about 330 deaths from lung cancer annually are attributable to such exposure.

Adult↗
PubMed1987

Important risk factors for death in adults: a 10-year follow-up of the Nutrition Canada survey cohort.

Data on mortality among over 8000 Canadians aged 35 to 79 years who participated in the Nutrition Canada survey are presented. The effects of various risk factors on mortality were assessed with a multivariate Poisson regression analysis. Factors associated with a significantly increased risk of death over a 10-year follow-up period ending in 1981 included cigarette smoking, hypertension and diabetes mellitus. A shallow U-shaped mortality pattern was observed for body mass index and for serum cholesterol level. No statistically significant increases in risk were associated with alcohol consumption. The population attributable risks for smoking, hypertension and diabetes were 39%, 8% and 6% respectively for men and 21%, 12% and 7% respectively for women.

Adult↗
PubMed1987

[Evolution of Quebec's mortality rates, by cause of death].

"The evolution of mortality in Quebec over the past three decades is reviewed. Life expectancies and potential years of life lost from birth to age 75 are calculated. Also, interprovincial comparisons of mortality are included. Quebec's mortality experience, in comparison to the other provinces, is poor. Causes of death that are of particular concern are suicide and lung cancer. Mortality rates for cerebrovascular diseases, stomach cancer and kidney diseases have markedly declined, for males as well as females." (SUMMARY IN ENG AND SPA)

Americas↗
PubMed1986

Cancer patterns in Canada.

Cancer is diagnosed in about 70 000 Canadians each year and is the leading cause of the loss of potential years of life before age 75 among women. Life-threatening forms of cancer will develop in at least one of every three Canadian newborns during their lifetimes if current cancer risks are not reduced. Lung and breast cancers are, respectively, the leading causes of premature death due to cancer among men and women. Compared with other countries Canada has low death rates for stomach cancer but high rates for certain smoking-related cancers (those of the lung and of the mouth and throat), leukemia and cancers of the colon, breast and lymphatic tissues. Newfoundland has the highest rates of death from stomach cancer and the lowest rates of death from prostatic cancer, whereas the western provinces have the opposite pattern. The rates of death from lung cancer among men are highest in Quebec, the province with the highest prevalence of smoking. In Canada the overall rates of death from cancer increased by 32% among men from 1951 to 1983. However, among women they declined by 12% from 1951 to 1976 and increased from 1976 to 1983, particularly among those aged 55 to 74. The rising rates of death due to lung cancer were primarily responsible for these increases. Lung cancer will likely displace breast cancer as the leading cancer killer of Canadian women by 1990. Given the relatively low survival rates for cancers caused by smoking and the lack of substantial improvement in rates for the most frequent types of cancer, preventive strategies that include effective measures to reduce tobacco consumption are urgently required.

Adult↗
PubMed1986

Risk factors for postneonatal mortality: results from a record linkage study.

A population-based computer record linkage of infant births and deaths was conducted for 1978 and 1979 covering Canadian provinces. Birthweight was inversely related to risk of postneonatal death for all causes examined, including accidental deaths. Length of gestation was inversely associated with risk, but the strength of the relationship was much weaker than that noted for birthweight. A logistic regression model was used to assess the effects of variables, as reported on birth certificates, on postneonatal mortality. Maternal age less than 25 years, unmarried marital status and one or more previous births were all statistically significantly related to increased risk.

Adult↗
PubMed1985

Risk factors for perinatal mortality in Canada.

A population-based computer record-linkage study of infant births and deaths in 1978 and 1979 in eight Canadian provinces (Quebec and Newfoundland were excluded) was undertaken to permit analysis of perinatal mortality in relation to maternal and infant characteristics. Perinatal mortality rates were significantly higher in nonurban than in urban areas (p less than 0.05). A logistic regression model was used to assess the effects on perinatal mortality of variables reported on birth and stillbirth records. This model included length of gestation, infant's birth weight and sex, number of previous births and number of previous stillbirths as well as an interaction term for length of gestation and birth weight. For early-neonatal mortality, odds ratios over 8 were observed for birth weight less than 2500 g or gestation less than 35 weeks. About 75% of early-neonatal mortality was attributable to low birth weight or fetal immaturity. Greater emphasis should be placed on the prevention of low birth weight.

Birth Weight↗
PubMed1981

Asbestos and drinking water in Canada.

Samples of raw, treated and distributed tap water were collected from 71 municipalities across Canada and analyzed for asbestos content by transmission electron microscopy. Chrysotile asbestos was identified as the major asbestos type present in drinking water with some 5% of public water supplies containing asbestos at concentrations greater than 10 million fibres per litre. Improvement factors of up to 300 were observed for the removal of chrysotile fibres from drinking water during treatment, indicating that coagulation/filtration treatment is efficient for this purpose. In certain cases there is evidence to suggest that erosion of asbestos from pipe material is taking place. Age-standardized mortality rates for gastro-intestinal cancers were calculated for each city for the period of 1966 to 1976. Rates for the 2 localities with the highest (congruent to 10(8)/L) concentrations of asbestos fibres in treated drinking water were compared with the weighted average of the rates for the 52 localities with asbestos concentrations not significantly greater than zero. Eleven localities had intermediate concentrations of asbestos and six were too small for meaningful statistical analysis. Relatively high mortality rates were apparent amongst males in city 1 for cancer of the large intestine except rectum, and in both sexes in city 1 and males in city 2 for stomach cancer. It is felt that these findings are probably related to occupational exposure to asbestos. Further statistical analyses are required, however, before the significance of these observations can be fully assessed.

Asbestos↗