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Biomedical subjects

T Abernathy

Publications and source records attributed to T Abernathy.

16 recordsLinked to original sources
PubMed1999

Associations between stomach cancer incidence and drinking water contamination with atrazine and nitrate in Ontario (Canada) agroecosystems, 1987-1991.

BACKGROUND: Nitrate and atrazine are two chemicals that are heavily used in certain sectors of agriculture. They are suspected to be associated with the development of certain types of tumours. METHODS: Existing data were obtained on the incidence of specific types of cancers, contamination of drinking water with atrazine and nitrate, and related agricultural practices for the 40 ecodistricts in the province of Ontario. The data were merged into a georelational database for geographical and statistical analyses. Weighted (by population size) least squares regression analyses were conducted while controlling for confounding socioeconomic and lifestyle factors. Maximum likelihood spatial error models were estimated when least square regression error terms were found to be spatially autocorrelated using the Moran's I statistic. RESULTS: Atrazine contamination levels (range 50-649 ng/l, maximum acceptable concentration [MAC] = 60000 ng/l) were positively associated (P < 0.05) with stomach cancer incidence and negatively associated with colon cancer incidence. Nitrate levels, (range 0-91 mg/l, MAC = 10 mg/l) were negatively associated with stomach cancer incidence. CONCLUSION: The associations found at the ecodistrict level, both positive and negative, if confirmed by other studies, raise serious questions about maximum allowable limits for atrazine, as well as possibilities of complex trade-offs among disease outcomes, and interactions of biophysical and social mechanisms which might explain them. Although the negative associations appear to have no direct biological explanations, such counter-intuitive outcomes may occur in complex systems where social and biological variables interact.

Adult↗
PubMed1999

Influence of companion animals on the physical and psychological health of older people: an analysis of a one-year longitudinal study.

OBJECTIVE: To examine whether companion animals or attachment to a companion animal was associated with changes in physical and psychological health in older people and whether the relationships between physical and psychological health and human social networks were modified by the presence or absence of a companion animal. DESIGN: A 1-year longitudinal study with standardized telephone interview data collected at baseline and repeated at 1-year SETTING: Wellington County, Ontario, Canada PARTICIPANTS: An age- and sex stratified random sample (baseline n = 1054; follow-up n = 995) of noninstitutionalized adults aged 65 and older (mean age = 73, SD +/- 6.3) MEASUREMENTS: Social Network Activity was measured using a family and non-family social support scale, participation in an organized social group, involvement in the affairs of the social group, the practice of confiding in others, feelings of loneliness, and the perceived presence of support in a crisis situation. Chronic conditions were measured as the current number of selected health problems. Pet ownership was assessed by the report of owning a dog or a cat and the Lexington Attachment to Pets Scale score. Physical health was assessed as the ability to perform Activities of Daily Living (ADLs). Psychological health was measured as a summed score comprising the level of satisfaction regarding one's health, family and friend relationships, job, finances, life in general, overall happiness, and perceived mental health. Sociodemographic variables assessed include subject age, sex, marital status, living arrangements, education, household income, and major life events. RESULTS: Pet owners were younger, currently married or living with someone, and more physically active than non-pet owners. The ADL level of respondents who did not currently own pets deteriorated more on average (beta = -.270, P = .040) than that of respondents who currently owned pets after adjusting for other variables during the 1-year period. No statistically significant direct association was observed between pet ownership and change in psychological well-being (P > .100). However, pet ownership significantly modified the relationship between social support and the change in psychological well-being (P = .001) over a 1-year period. CONCLUSIONS: The results demonstrate the benefits of pet ownership in maintaining or slightly enhancing ADL levels of older people. However, a more complex relationship was observed between pet ownership and an older person's well-being.

Aged↗
PubMed1999

Analysis of factors related to illegal tobacco sales to young people in Ontario.

OBJECTIVE: To identify and to discuss factors influencing illegal merchant sales of tobacco to underage people in Ontario, Canada. DESIGN: Results were obtained through random retail compliance checks of tobacco merchants. A multivariate analysis specified the relationship between selected independent variables and the willingness of tobacco merchants to sell to minors. The selected independent variables included retail operation type, community population size, the presence of tobacco production, signage, sex and age of volunteers, smoking prevalence rates, and enforcement rates. PARTICIPANTS: A random, stratified sample of 438 tobacco retailers in 186 communities in Ontario. MAIN OUTCOME MEASURE: Willingness of merchants to sell tobacco to minors. RESULTS: Older youths and girls were more likely to be sold tobacco products. Purchase attempts carried out in tobacco-producing regions were also statistically related to illegal sales. CONCLUSIONS: Policy efforts to control youth access to tobacco in Canada may need to invoke legislation requiring merchants to request proper identification from customers who appear to be under the age of 25, and who seek to purchase tobacco products. Further attention could also be directed at tobacco control policies and enforcement strategies that need to consider the unique challenges faced by jurisdictions where the tobacco industry is a powerful presence.

Adolescent↗
PubMed1996

Polymers with Very Low Polydispersities from Atom Transfer Radical Polymerization

A radical polymerization process that yields well-defined polymers normally obtained only through anionic polymerizations is reported. Atom transfer radical polymerizations of styrene were conducted with several solubilizing ligands for the copper(I) halides: 4,4'-di-tert-butyl, 4,4'-di-n-heptyl, and 4,4'-di-(5-nonyl)-2,2'-dipyridyl. The resulting polymerizations have all of the characteristics of a living polymerization and displayed linear semilogarithmic kinetic plots, a linear correlation between the number-average molecular weight and the monomer conversion, and low polydispersities (ratio of the weight-average to number-average molecular weights of 1.04 to 1.05). Similar results were obtained for the polymerization of acrylates.

Journal Article↗
PubMed1995

Is quinine effective and safe in leg cramps?

Muscle cramp is a recurrent and painful condition and a common complaint among elderly subjects and patients treated with hemodialysis. It is commonly nocturnal and can disturb a good night's sleep. No specific cause can be identified; therefore, therapy is mostly symptomatic. Quinine sulfate, an antimalarial drug, is widely used as an effective therapy for idiopathic leg cramps. Several double-blind, randomized, placebo-controlled studies have questioned the effectiveness of quinine in leg cramps; whereas other studies have shown significantly more benefit with use of quinine in reducing the frequency and severity of cramps compared with placebo or vitamin E. The mechanism of this beneficial effect is obscure, however. Quinine appears to decrease the excitability of the motor end plate, thereby reducing the muscle contractility. Most patients consider quinine beneficial for their leg cramps, which is difficult to refute by scientific data. More important, cramp is a subjective symptom, therefore difficult to measure objectively. Consequently, scientific studies designed to prove or disprove the effectiveness of quinine can be subject to flaws. Further, a dosage of 200 to 300 mg of quinine every night has not been shown to cause significant side effects. Nevertheless, quinine should be used in a small dose and cautiously, especially in the elderly and patients with renal failure, and should be avoided in patients with liver disease.

Aged↗
PubMed1994

Sequence of sexual behavior and its relationship to other problem behaviors in African American and Puerto Rican adolescents.

This study examined the sequence of sexual behavior of 695 African American and 637 Puerto Rican adolescents and the relationship of this sequence to other problem behavior measures. Analyses indicated that adolescents proceed through four stages of sexual behavior: no involvement, then deep kissing, then petting, and, finally, sexual intercourse. The sequence was similar in both ethnic groups and seemed both unidimensional and cumulative. In addition, for both ethnic groups the degree of sexual involvement was significantly related to the level of drug use and to the frequency of delinquent behavior, thereby suggesting an underlying problem behavior syndrome. Directions for future research are suggested.

Adolescent↗
PubMed1988

Birth patterns: are the Chinese in Guangzhou City different?

Diurnal birth patterns in the City of Guangzhou, China and the City of Calgary in Canada were compared. Chinese data were abstracted from the labor room log book of one large general hospital located in the Hai Zhu district of Guangzhou. Calgary birth data were abstracted from birth notification forms submitted to Calgary Health Services. Information included day of birth, time of delivery, type of delivery and parity. Calgary births are concentrated on Tuesdays to Fridays whereas in Guangzhou weekly patterns varied tremendously according to whether it was assisted or unassisted. Calgary births are below average at night and during evening shift. The time of birth in Guangzhou varied substantially with above average rates for non-assisted births noted at 0800-2400 h, and above average rates for assisted births noted at 0800-1700 h. Differences in hour of birth appeared to be related to obstetric intervention practices. Knowledge of birthing patterns are useful for effective hospital management.

Canada↗
PubMedDate not supplied

The effects of prehospital advanced life support drug treatment on patient improvement and in-hospital utilization.

OBJECTIVE: There is little published evidence to support the benefits of prehospital drug administration by ambulance personnel in reducing subsequent hospital utilization by the medical patients receiving such drugs. The authors studied the outcome of patients treated by Ontario's Emergency Health Services "Symptom Relief Drug Program," which was developed to relieve patient symptoms in the field for specific medical emergencies. METHODS: A retrospective study spanning a three-year period from January 1996 to December 1998 was undertaken in a mid-sized southern Ontario community. From a review of ambulance call reports (ACRs), eligible patients were recruited by mail and divided into two groups: those treated before the introduction of the program (pre) and those treated after (post). Out-of-hospital data were retrieved from ACRs and in-hospital data were gathered from medical chart reviews. Outcomes included emergency department (ED) length of stay (LOS), frequency of admissions, and departmental use. Secondary endpoints included differences in prehospital improvement, ED interventions, and ambulance scene times. RESULTS: For the unpaired analysis, 406 patients provided consent (pre: 215 vs post: 191). Ambulance time on scene was longer in the post group, 14.2 minutes (95%CI 13.7-14.8), versus the pre group, 12.3 minutes (95% CI 11.7-12.9), p < 0.001. A larger proportion of patients receiving prehospital drug treatment were judged to have improved on ED arrival (pre: 19.5% vs post: 48.2%, chi2 p < 0.0001). The ED LOSs did not differ between groups (pre: 206.9 min, 95% CI 185.9-230.4, vs post: 220.9 min, 95% CI 196.9-247.7, p = 0.42) but were shorter within the post group for hypoglycemic patients receiving glucagon. The overall proportion of admissions was significantly lower in the post group (pre: 145 [67.4%] vs post: 102 [54.3%], chi2 p < 0.01), and this was driven by chest pain patients. CONCLUSIONS: The lower rate of admissions for chest pain patients is the first published evidence of prehospital drug treatment's reducing hospital utilization in a sub-group of such medical patients. The "Symptom Relief Drug Program" is effective in improving patients' field conditions and can decrease ED LOS in hypoglycemic persons receiving glucagon injections. More outcome research pertaining to ambulance-administered prehospital drug treatment is warranted.

Aged↗
PubMedDate not supplied

Public health inspectors in restaurants: what they do and why.

This report identifies strategies used by public health inspectors in the Central West Region of Ontario during restaurant inspections, based on and comparing the perceptions of inspectors, their managers, and restaurant operators. Factors influencing the choice of strategies are reviewed, putting into perspective the importance of manager and policy expectations relative to other influences experienced by inspectors in the field. The need to set pragmatic and reality-tested criteria and objectives for a HACCP-based inspection protocol is discussed.

Facility Regulation and Control↗
PubMedDate not supplied

How reliable are selected scales from population-based health surveys? An analysis among seniors.

The objective of the study was to assess the internal consistency and test-retest reliability of selected scales from four national and provincial surveys used to study the health status of community-dwelling seniors. Items on physical impairment, psychological well-being, activities of daily living, chronic health problems, social support, and stressful life events were selected from these surveys and administered in a group of 1,054 seniors, aged 65 and over, living in Wellington County, Ontario. Each scale exhibited high internal consistency (Cronbach's alpha > or = 0.70) except for the stressful life events and social support scales. The intra-class coefficients (rho) for all scales were > 0.80. In addition, almost all single items measures used in this study also exhibited high test-retest reliability (kappa > 0.80) except for measures of perceived health status (kappa = 0.69) and availability of help in crisis situation (kappa = 0.48).

Activities of Daily Living↗
PubMedDate not supplied

Analysis of factors related to development, regulatory level and change in municipal no-smoking by-laws in Ontario.

OBJECTIVES: This study explored and measured the presence, content and growth of municipal no-smoking by-laws and examined factors related to differences in by-law breadth and comprehensiveness. METHODS: By-laws from each jurisdiction across Ontario were collected and scored relative to their breadth and restrictiveness using the Asbridge-O'Grady Index. Kruskal-Wallis analysis of variance was used to compare the distributions of municipal characteristics among the regulatory level of municipal smoking legislation. RESULTS: Twenty-three percent of Ontario municipalities (215/951) had enacted smoking by-laws by the end of 1998 compared to 18% (169/951) in 1994. Larger municipalities tend to be significantly more restrictive than smaller municipalities. CONCLUSION: No-smoking legislation has become more extensive and restrictive in Ontario since the passage of the 1994 Tobacco Control Act. There was little legislative variability among the regions that contained tobacco-producing municipalities and those that did not.

Humans↗
PubMedDate not supplied

A comprehensive evaluation of the 1993 city of Toronto smoking by-laws.

Effective January 1, 1993, the City of Toronto's two smoking by-laws--one regarding workplaces and another regarding public places--were replaced and amended respectively. Smoking is now prohibited in all workplaces (unless in a designated smoking area), and in at least 50% of eating areas in restaurants. Through a workplace telephone survey and restaurant inspection records, the implementation and enforcement of the by-laws were evaluated. Eighty-three per cent of the workplaces were completely smoke-free and 7% had restricted smoking to a designated area. A majority (76%) of the managers and owners were in favour of regulatory controls on smoking in workplaces. Eighty-six per cent of restaurants complied with requirements for a minimum 50% smoke-free area and signage, and nearly 4% of the sampled restaurants banned smoking throughout the entire premises even though this is not currently required.

Constitution and Bylaws↗
PubMedDate not supplied

Using a breastfeeding prevalence survey to identify a population for targeted programs.

Often, efforts to improve overall population health require identifying and targeting programs to specific high-risk populations. Breastfeeding is an example. In order to determine initiation and duration rates among various groups in the City of Toronto, a random sample of 434 mothers with infants at four months of age was surveyed to determine the prevalence of breastfeeding and major impacts on its duration. The study found that, overall, 83% of mothers initiated breastfeeding at birth. The greatest rate of decline occurred during the first month. At four months postpartum, 57% of mothers continued to breastfeed, including 35% who were exclusively breastfeeding and 22% who were supplementing breast milk with formula. Breastfeeding duration was related to a number of factors, including information and support, parity, education, use of formula supplements and country of birth. Specific groups are identified for targeted programs, and a number of strategies are proposed.

Adult↗