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[Problems in using survival data of cancer patients as a method of gauging the effectiveness of cancer control efforts].

Survival rates of cancer patients have been widely used as a method of gauging the effectiveness of cancer control efforts. Sometimes, however, they cannot be considered reliable indicators due to many biases, such as a lead time bias, a length bias, a self-selection bias and an overdiagnosis bias. Instead, cancer mortality rates should be used for evaluating screening programs and for assessing the recent progress against cancer, although some problems are encountered in the accuracy of death certificates.

Humans↗

The association of health with stressful life changes, social supports, and coping.

Cross-sectional associations of social stressors, social supports, and coping strategies with health status were explored in a self-selected sample of 157 white adults. Using a mailed questionnaire, stressful life changes were assessed by a 40-item version of the Social Readjustment Rating Scale, social supports were measured by a 13-item index, and health status was assessed by the 63-item Duke-UNC Health Profile (DUHP). Responses to a recent stressful event were categorized by method of coping and by focus of coping. In a multivariate analysis controlling for the effects of age, gender, and education level, higher 12 month life change score was related to lower composite DUHP score. The use of active-cognitive coping was directly associated and the use of avoidance-coping was inversely associated with health status. When interaction terms were included in the multivariate analysis, avoidance-coping potentiated the adverse health effect of stressors and weak social supports potentiated the harmful effect of avoidance-coping on health. The findings suggest that the propensity to engage in avoidant behavior in response to a stressful experience is associated with health impairment, particularly when social supports are weak.

Adaptation, Psychological↗

Referrals and notifications by British optometrists.

1031 British optometrists completed a questionnaire to give information on their rates of referral and notification to the medical profession. Data were collected in relation to the conditions concerned, the age and sex of the patient, and the spectacle correction. Major causes of referral were cataract, glaucoma, fundus changes, headaches/migraine/eye pain and lowered visual acuity; 6.5% of all patients seen were referred to their general medical practitioner notified, and of this group it was estimated that 25-30% could have managed with reading glasses which comprised spherical lenses of equal power. If such glasses could be self-selected, without reference to a medical practitioner or optometrist, a significant number of people would not benefit from the health screening aspects of the eye examination.

Adolescent↗

South African health care and the proprietary medicine industry.

A large-scale national sample survey was conducted to assess the health and sickness profiles of the population by conventional demographic parameters. The objective was to ascertain how people treated particular ailments and in particular how and when they used proprietary medicines and other self-medication alternatives rather than a professional medical practitioner. The attitudes to self-medication by the respondents were largely positive. Self-selected treatments were perceived to be successful. A panel of physicians was asked to comment on the medical suitability of the ailments chosen for self-treatment and of the medicines selected. People were deemed generally to administer self-medication responsibly and sensibly and in the case of more serious ailments did, correctly, consult professionals.

Adolescent↗

Effects of gastric bubble implant on weight change with and without compliance with a behavior modification program.

The purpose of this prospective study was to evaluate the effect of compliance versus noncompliance with a behavior modification program (BMP) for 35 patients who underwent implantation of 51 Garren-Edwards gastric bubbles (GEGB). Criteria for morbid obesity was met by every patient. Two patient groups were formed by self-selection. Compliant patients (group I) attended 75% or more of the BMP. Group II consisted of noncompliant patients, and was divided further into partially complaint and totally noncompliant. A significant difference was found in both loss of weight and loss of body mass index (BMI) between the complaint and noncompliant groups, with no significant difference in weight loss between the partially and totally noncompliant groups. Patients' compliant or noncompliant behavior had a significant effect on changes in weight (p = 0.007) and body mass index (p = 0.005). Sixteen patients had two consecutive bubble implants. The rate of compliance was significantly higher during the first implant program, with a significantly greater loss in both weight and BMI for compliant patients. Follow-up data for 28 of 35 patients revealed a continued, albeit small, average weight decrease. In summary, weight loss does not result from the gastric bubble alone. Our study demonstrates that the key factor is compliance with a behavior modification program.

Adolescent↗

Correlates of adolescent parenting.

A self-selected sample of 177 teenage parents participated in a study of the correlates of teenage parenting. An ecological model of the predictors of parenting behavior was used to define factors which potentially influence teenage parents' parenting skills as measured by the Home Observation for Measurement of the Environment (HOME). The factors tested include level of punitiveness toward child rearing, knowledge of developmental milestones, level of depression, perceived social support, parental age, and parental race. The results of a stepwise hierarchical regression analysis found that parental race, punitive attitudes toward child rearing, and parental age were statistically significant predictors of total HOME scores. The older, white adolescent mother with less punitive attitudes toward child rearing and child discipline scored the highest on parenting skills. The relevance of these findings to program planners and service providers involved in teenage parent support and education programs is discussed.

Adolescent↗

Reported frequency of dairy farm-associated health hazards, Otsego County, New York, 1982-1983.

We surveyed a self-selected sample of dairy farm owners/residents to determine the feasibility of establishing a surveillance system that would identify health risks common to this type of farming activity. Data obtained included demographic characteristics of the farm families, number of milk cows, prevalence of selected respiratory diseases, and farm-related injuries among farm owners. Despite a low overall response rate (45 percent), farm owners/residents reported a higher prevalence of respiratory conditions than that of the United States as a whole. Male farm owners were less likely to smoke than U.S. white males as a whole. The number of farm owners reporting farm-related injuries during a one-year period (9 percent) was similar to previous reports.

Animals↗

Results of a second-opinion program for coronary artery bypass graft surgery.

Second opinions for surgical procedures are now being sought by patients or are required by insurance carriers. We examined outcomes among 88 patients (76 men; average age, 59 years) referred for a second opinion as to the need for coronary artery bypass graft surgery. All patients had undergone coronary arteriography, which disclosed in 63 (72%) multivessel coronary artery disease, while in the remaining 25 patients single-vessel disease involved the left anterior descending coronary artery. Continuation of medical therapy was recommended for 74 (84%) of the 88 patients. Sixty of these 74 patients chose this option and continued to receive medical therapy without any fatalities during a follow-up period of 27.8 months. The remaining 14 patients elected to cross over to surgical therapy at an average of 11.3 months from the second opinion. We conclude that second opinions for selected, motivated patients slated for coronary artery bypass graft operation afford a significant and safe option. Moreover, a majority of patients will adhere to a second opinion recommending medical therapy, thus reducing the need for surgical intervention by as much as 50%. Since the study was based on a small sample size of self-selected patients, these data require caution in extrapolating to the general population with coronary artery disease.

Adult↗

Prevalence of hepatitis B markers in occupational health nurses.

A seroprevalence study was undertaken at the 14th Annual Conference of the Occupational Health Nurses Association of Ontario. A total of 151 self-selected registrants (33%) provided demographic, health, and occupational information. Blood was drawn for hepatitis B serology (hepatitis B surface antigen, core antibody, and surface antibody). Vaccine-induced seropositivity was found in 11 persons (7.3%) while naturally occurring markers were present in 13 nurses (8.6%). This exceeds the natural prevalence of markers in Canada (4% to 6%) but is less than that seen in emergency and renal dialysis nurses. It implies that occupational health nurses are at less risk for hepatitis B virus infection than their acute care hospital colleagues.

Adult↗

Leisure-time physical activity levels and risk of coronary heart disease and death. The Multiple Risk Factor Intervention Trial.

The relation of self-selected leisure-time physical activity (LTPA) to first major coronary heart disease (CHD) events and overall mortality was studied in 12,138 middle-aged men participating in the Multiple Risk Factor Intervention Trial. Total LTPA over the preceding year was quantitated in mean minutes per day at baseline by questionnaire, with subjects classified into tertiles (low, moderate, and high) based on LTPA distribution. During seven years of follow-up, moderate LTPA was associated with 63% as many fatal CHD events and sudden deaths, and 70% as many total deaths as low LTPA (P less than .01). Mortality rates with high LTPA were similar to those in moderate LTPA; however, combined fatal and nonfatal major CHD events were 20% lower with high as compared with low LTPA (P less than .05). These risk differentials persisted after statistical adjustments for possible confounding variables, including other baseline risk factors and Multiple Risk Factor Intervention Trial group assignments. It is concluded that LTPA has a modest inverse relation to CHD and overall mortality in middle-aged men at high risk for CHD.

Adult↗

A survey of 311 patients receiving ibopamine mainly during hospital treatment for severe congestive heart failure.

From a monitored release of ibopamine, the 3,4-diisobutyryl ester of N-methyldopamine, during the early Italian marketing of the drug a collection of 311 individual cases was formed. The cases were reported by 168 cardiologist-practitioners, self-selected for having a therapeutic interest in the inotropic properties of ibopamine and in trying it out in patients with mostly severe, refractory congestive heart failure (CHF). Most patients were monitored during a hospital admission for worsened CHF. After clinical reassessment and other drugs' adjustment, ibopamine was added and the patient followed-up for 20 days in hospital with regular recording of scored signs and symptoms, arterial pressure, heart rate, body weight, and any clinical event--adverse or beneficial. Concomitant drugs were also recorded. Global assessment of efficacy was mostly positive, with "ineffective" rates of only 15.9% (doctors) and 14.2% (patients). In the absence of a control group, it is impossible to determine to what extent the foregoing was really due to ibopamine or to the rest of the therapeutic policy. However, the fact that most of the severe cases had been refractory to prior treatment, and that they individually carried a grave prognosis on admission, do seem to point to real ibopamine-related benefit. The high rate of symptomatic benefit perceived by the patients would also seem likely to be drug-related. Heart rate after the ibopamine-including regimen was significantly lower than before. Systolic and diastolic arterial pressures also tended to decrease, especially in CHF of hypertensive etiology.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

Human growth hormone release is decreased during sleep in temporal isolation (free-running).

Growth hormone (hGH) secretion was measured during sleep in 10 healthy male subjects isolated from all time cues. HGH concentrations following sleep onset were compared between scheduled sleep episodes (entrainment) and self-selected sleep episodes (free-running). Peak sleep-related hGH values were decreased significantly during free-running. The duration of the first slow wave sleep (SWS) episode and the latency to the first REM sleep episode also decreased significantly during free-running. The latencies from sleep onset to SWS and to peak hGH secretion did not differ between entrainment and free-running. These results suggest that sleep-related hGH secretion begins 'on time' during free-running, but is terminated earlier. Thus, while sleep onset facilitates hGH release, the timing of other stages of sleep such as REM may alter the magnitude of sleep-related hGH secretion.

Adult↗

Reduced tar, nicotine, and carbon monoxide exposure while smoking ultralow- but not low-yield cigarettes.

An unresolved public health issue is whether some modern cigarettes are less hazardous than others and whether patients who cannot stop smoking should be advised to switch to lower-yield cigarettes. We studied "tar" (estimated by urine mutagenicity), nicotine, and carbon monoxide exposure in habitual smokers switched from their usual brand to high- (15 mg of tar), low- (5 mg of tar), or ultralow-yield (1 mg of tar) cigarettes. There were no differences in exposure comparing high- or low-yield cigarettes, but tar and nicotine exposures were reduced by 49% and 56%, respectively, and carbon monoxide exposure by 36% while smoking ultralow-yield cigarettes. Similarly, in 248 subjects smoking their self-selected brand, nicotine intake, estimated by blood concentrations of its metabolite cotinine, was 40% lower in those who smoked ultralow but no different in those smoking higher yields of cigarettes. Our data indicate that ultralow-yield cigarettes do deliver substantial doses of tar, nicotine, and carbon monoxide, but that exposures are considerably less than for other cigarettes.

Adult↗

Effects of a low-fat diet on plasma lipoprotein levels.

Lowering the intake of fat to decrease serum cholesterol levels has unknown effects on the proportion of cholesterol in low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Twenty normolipidemic nonvegetarians were given dietary instruction and supervision in a low-fat, semivegetarian diet for three months. Mean consumption of total fat, saturated fat, and cholesterol decreased, whereas intake of carbohydrate increased significantly on a low-fat diet. Plasma LDL levels decreased by 18% and HDL levels by 7% from prestudy baseline levels. The LDL/HDL ratio declined by 11%. Plasma triglyceride levels and body weight were unchanged. In individual subjects, the decrements in consumption of saturated fat and the increments in ingestion of polyunsaturated fat were each significantly correlated with decreases in LDL. One year after the subjects had returned to a self-selected diet, levels of dietary saturated fat and cholesterol and the plasma LDL/HDL ratio remained significantly below prestudy levels. This study and others suggest that a low-fat, high-carbohydrate diet favorably affects the plasma LDL/HDL proportion by decreasing LDL on a percentage basis 2 1/2 to three times more than it decreases HDL.

Adolescent↗

Population screening for cholesterol determination. A pilot study.

A screening for plasma cholesterol levels was conducted at six sites in the New York metropolitan area and involved hospitals, health professionals, paraprofessionals, media experts, and instruments that provided cholesterol levels rapidly. During the five days of the testing, over 12,000 participants were screened. Because the program was limited to customary working hours and because of self-selection of participants, the subjects were probably an unusually health-conscious group as evidenced by the low prevalence of cigarette smokers (11%). Nevertheless, 12% were at moderate risk and 16% were at high risk for coronary heart disease. Approximately half of the population reported never having had their cholesterol levels tested, and over 40% had no idea what levels were optimal. A subsample of patients at risk was screened by telephone survey. In the majority of cases, when a patient's physician was consulted for advice, no action was recommended. Our results demonstrate that a large population screening can be implemented, that at least certain segments of the public will respond to such a program, and that educational efforts must be directed at both the public at large and physicians.

Adult↗

The natural history of sensitivity to jack jumper ants (Hymenoptera formicidae Myrmecia pilosula) in Tasmania.

There are no records of the natural history of allergic reactions to "jack jumper ant" (Myrmecia pilosula) stings, but a letter to Tasmanian newspapers asked that persons who had not received prophylactic injections for such stings to report any reactions that they had experienced. Two hundred replies were received from a population of 400,000 persons, which shows that these reactions are widespread and that victims are often terrified at the thought of a further sting. Persons who responded were sent a circular and their reactions were classified. The first 100 replies were analysed: 49 persons reported an immediate generalized reaction from the first sting; 31 of these 49 persons and 18 others had a generalized reaction to further stings; and there was a tendency for local reactions at the sting site to become generalized to the whole body. Of the 15 persons who had had no reaction to a first sting, 12 claimed to have developed a generalized reaction on receiving a subsequent sting. Although self-selection may have provided an exaggerated view of the frequency with which reactions to the stings of jack jumper ants become generalized, the problem is clearly one of considerable magnitude which requires further research and attention.

Adult↗

Specialties chosen by medical students who participated in a student-run, community-based free clinic.

Since 1974 the Hispanic medical and premedical students at the University of California, Davis, have operated a free clinic in a Hispanic community in Sacramento with the support and assistance of the family practice department. Using National Residency Matching Program data for the years 1978-1982, we compared the specialties selected by the students who had participated in Clinica Tepati for elective credit with those selected by all other graduating students. Almost all of the Clinica Tepati students (96.5 percent) selected one of the primary care specialties--family practice, pediatrics, and internal medicine--with 55.2 percent selecting family practice. These specialty choices of the Clinica Tepati students were significantly different from those of the other students. No cause-and-effect relationship can be determined when studying a self-selected group of students, yet the large percentage of the Clinica Tepati students selecting primary care does point toward such community-oriented experiences having some value in motivating or reinforcing a student's choice of primary care as a career goal.

California↗

Avoidance of bias in cohort studies.

Cohort studies have particular advantages in confirming results of retrospective or case-control studies in those situations in which case-control studies are no longer feasible. In circumstances, the cohort study may involve randomization, thus reducing selection bias, but ordinarily there will have been self-selection by individuals as to the group in which they will fall. Investigators should analyze data from a cohort study so as to take the passage of time into account. Variables anticipated to have effects should be accounted for by stratification, if feasible, or by mathematical modeling, if necessary. Results should be interpreted with care, and qualifications should be made on any interpretations, including qualifications relating to the propriety of the mathematical model used. When long latencies are a factor, and particularly when exposure is initiated late in life, establishment of a positive role for the exposure can be difficult. Case-control and other epidemiologic studies are biased toward identification of exposures leading to outcomes of a unique nature but fail to identify more serious exposures with adverse outcomes which are more commonplace.

Clinical Trials as Topic↗