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At least 19 recordsLinked to original sources
PubMed1975

Attributable risk, population attributable risk, and population attributable fraction of death associated with hypertension in a biracial population.

In 1961, blood pressure was measured in the 40-69-year-old segment of the population of Evans County, Georgia. Mortality was monitored for up to ten years. The relationship found between hypertension and mortality is characterized in this report by four parameters: attributable risk, prevalence, population attributable risk, and population attributable fraction. Attributable risk of death, a measure of the over-all impact of hypertension on those in each race-sex group with hypertension, is high in white males, black males, and black females, and is lowest in white females. Population attributable risk, a measure of the impact of hypertension on each entire race-sex group, is highest in black males and females due to the high prevalence of hypertension in blacks. It is somewhat lower in white males and lowest in white females. The fraction of all deaths attributable to hypertension (population attributable fraction) is highest in black females and lower in the other three groups. The population attributable fraction (ranging from 0.26 to 0.54 for systolic hypertension) is of such magnitude that if the 50% reduction in mortality achieved in the Veteran Administration Cooperative Study could be repeated in the general population, life expectancy after 40 years of age could be substantially increased.

Adult↗
PubMed1996

Nasopharyngeal cancer in a low-risk population: defining risk factors by histological type.

Nasopharyngeal cancer (NPC) is a major public health problem in parts of Southeast Asia and North Africa, but is rare among whites and blacks. Although infection with the EBV and genetic susceptibility appear to play large roles in high-incidence populations, migrant studies suggest that environmental factors may also be important. Aside from the high risks associated with ingestion of salted fish, surprisingly few other risk factors have been established from studies in endemic areas. We studied a low-incidence population to determine whether tobacco use, alcohol consumption, and certain medical conditions and treatments are related to NPC and to examine variations in risk by histology. We reasoned that new relationships might be best identified in the absence of strong causal pathways, such as intake of preserved foods and genetic susceptibility. A population-based case-control study was conducted from 1987 to 1993 at five cancer registries in the United States: western Washington, metropolitan Detroit, Connecticut, Iowa, and Utah. Controls were identified by random digit dialing and frequency matched to the gender and age distribution of cases at each registry. Telephone interviews were completed by 231 cases and 246 controls. We observed a strong dose-response relationship between cigarette smoking and risk of differentiated squamous cell carcinoma (test for trend, P < .001). The highest risk [odds ratio (OR), 6.5; 95% confidence interval (CI), 2.0-21.3] occurred among current smokers with a history of more than 60 pack-years. In contrast, there was no evidence that undifferentiated or nonkeratinizing carcinomas were associated with cigarette smoking. Similarly, a significant increase in risk was observed for the heaviest alcohol consumers (21 or more drinks/week) only for differentiated squamous cell carcinomas (OR, 2.9; 95% CI, 1.2-6.9). The associations with cigarettes and alcohol appeared to be stronger among persons 50 years or older. There was a suggestion that diagnosis with infectious mononucleosis (a marker of late infection with EBV) is linked with decreased NPC risk (OR, 0.4; 95% CI, 0.1-1.1). This report indicates that over two-thirds of differentiated squamous cell NPC cases arising in older persons in the United States can be accounted for by cigarettes and alcohol, but leaves unexplained cases arising in the young and carcinomas of undifferentiated or nonkeratinizing histology. Future studies of NPC need to take into account histology and age in evaluating these and other environmental and genetic risk factors.

Adult↗
PubMed1984

Precursor lesions of oesophageal cancer in a low-risk population in China: comparison with high-risk populations.

An endoscopic survey was undertaken in Jiaoxian, People's Republic of China, a population at low risk for oesophageal cancer, to determine the prevalence of precancerous lesions of the oesophagus, and this rate was compared with the prevalence observed previously in high-risk populations in Iran and Linxian, China. The study involved 252 subjects whose exposure to suspected risk factors was determined by a questionnaire and all of whom underwent physical examination and oesophagoscopy, including cytology and biopsy. Chronic oesophagitis, with endoscopic and histologic characteristics similar to those observed in the high-risk populations of Iran and Linxian, was found in 28% of the study subjects compared to 80% in Iran and 65% in Linxian. Oesophagitis accompanied by atrophy of the epithelium was found in 0.4% compared to 10.5% in Iran and 10.8% in Linxian. No case of dysplasia was diagnosed in Jiaoxian while this condition was diagnosed in 4% of the subjects examined in Iran and in 8% of those in Linxian. The findings suggest that these lesions are in fact precancerous. Vitamin analysis showed that riboflavin deficiency was widespread in Jiaoxian, as in Iran and Linxian, but was more severe in Linxian than in Jiaoxian. No significant difference was found in the mean levels of retinol, beta-carotene and zinc between the two populations.

Adolescent↗
PubMed1991

Routine examination by ultrasound for the detection of fetal malformations in a low risk population.

A low risk population was offered screening for malformations in the second and third trimesters of pregnancy. Of 16,763 scans of pregnancies in the second trimester, 61 malformations were identified (0.36%). In the third trimester, scanning of 10,752 pregnancies revealed 24 malformations (0.22%): in all, in a low risk population 0.58% major malformations were found. The sensitivity for noncardiac malformations of the second trimester scanning was 54.3 with a specificity of 99.9%. The malformations overlooked was a more benign spectrum than the cases diagnosed. The sensitivity for cardiac malformations was less than 20%.

Congenital Abnormalities↗
PubMed1980

Metabolic epidemiology of large bowel cancer. Fecal mutagens in high- and low-risk population for colon cancer. A preliminary report.

Because of potential significance of fecal mutagens in the pathogenesis of colon cancer, the dietary pattern and fecal mutagens of 3 populations with distinct risk for the development of colon cancer, a high-risk population in New York Metropolitan area (non-Seventh-Day Adventists), a low-risk population of vegetarian Seventh-Day Adventists in New York Metropolitan area and a low-risk population in rural Kuopio, Finland were studied. The average daily intake of protein was the same in the 3 groups, but the sources were different, a greater portion coming from meat in the New York non-Seventh-Day Adventists and from vegetables in Seventh-Day Adventists. The intake of fat was lower in Seventh-Day Adventists and higher in Kuopio and in New York non-Seventh-Day Adventists. The intake of dietary fiber was high in Kuopio compared to other groups. Fecal samples collected for 2 days were freeze-dried extracted with peroxide-free diethyl ether, partially purified on a silica-gel column and assayed for mutagenicity using the Salmonella/mammalian microsome mutagenicity test. The mutagenic activity was observed with Salmonella typhimurium tester strain TA98 without microsomal activation and with TA100 with and without microsomal activation in high-risk subjects from New York consuming a high-fat, high-meat diet. The incidence of fecal mutagen activity was higher in volunteers from New York consuming a high-fat, high-meat diet compared to low-risk rural Kuopio population. None of the vegetarian Seventh-Day Adventists showed any mutagenic activity.

Adult↗
PubMed1987

Dracunculiasis in Africa in 1986: its geographic extent, incidence, and at-risk population.

This paper presents a preliminary assessment of the geographic extent and estimates of the incidence and the population at risk of dracunculiasis in Africa. Nineteen countries are known to be affected, in a belt extending right across the northern part of the continent south of 18 degrees N, and in east Africa extending almost to the equator. Annual incidence is estimated to be 3.32 million, and the at-risk population is approximately 120 million. These data provide an initial baseline on which the success of control measures now being initiated in Africa can be assessed.

Africa↗
PubMed1997

Are risk factors for conversion to NIDDM similar in high and low risk populations?

Mexican Americans have an increased risk of non-insulin-dependent diabetes mellitus (NIDDM) relative to non-Hispanic whites which is only partially explained by their excess overall obesity and unfavourable body fat distribution. Non-diabetic Mexican Americans have hyperinsulinaemia and insulin resistance relative to non-Hispanic whites. We therefore hypothesized that the insulin resistance might be a more important predictor of NIDDM in high-risk populations characterized by obesity and insulin resistance, while compromised insulin secretion might be a more important risk factor for NIDDM in low-risk populations. We assessed the ability of ethnicity (Mexican American vs non-Hispanic white), age, overall adiposity (body mass index [BMI]), unfavourable body fat distribution (as assessed by waist-to-hip ratio [WHR]), glucose tolerance (impaired glucose tolerance vs normal glucose tolerance), fasting insulin and compromised insulin secretion (as assessed by increment in insulin to the increment in glucose over the first 30 min of an oral glucose tolerance test (delta I30/delta G30)) to predict future NIDDM. In the 8-year follow-up of the San Antonio Heart Study, NIDDM developed in 11.7% (107/914) of Mexican Americans and in 5.0% (18/362) of non-Hispanic whites (p < 0.001). Multivariate predictors of NIDDM by multiple logistic regression analysis included increased age, BMI, WHR, fasting insulin and impaired glucose tolerance and decreased insulin secretion. The strongest independent predictors of NIDDM were high fasting insulin and decreased insulin secretion. These risk factors predicted NIDDM equally well in high and low-risk populations.

Adult↗
PubMed1996

The population risk as an explanatory variable in research synthesis of clinical trials.

The population risk, for example the control group mortality rate, is an aggregate measurement of many important attributes of a clinical trial, such as the general health of the patients treated and the experience of the staff performing the trial. Plotting measurements of the population risk against the treatment effect estimates for a group of clinical trials may reveal an apparent association, suggesting that differences in the population risk might explain heterogeneity in the results of clinical trials. In this paper we consider using estimates of population risk to explain treatment effect heterogeneity, and show that using these estimates as fixed covariates will result in bias. This bias depends on the treatment effect and population risk definitions chosen, and the magnitude of measurement errors. To account for the effect of measurement error, we represent clinical trials in a bivariate two-level hierarchical model, and show how to estimate the parameters of the model by both maximum likelihood and Bayes procedures. We use two examples to demonstrate the method.

Adrenergic beta-Agonists↗
PubMed1994

Proinsulin and specific insulin concentration in high- and low-risk populations for NIDDM.

Hyperinsulinemia and insulin resistance have been implicated as risk factors for the development of non-insulin-dependent diabetes mellitus (NIDDM). Recent data suggest that proinsulin may comprise a large proportion of immunoreactive insulin in subjects with NIDDM and possibly in those with impaired glucose tolerance (IGT) as well. Increased proinsulin concentrations are thought to be an early indicator of a failing pancreas. We examined proinsulin, insulin (using an assay that does not display appreciable cross-reactivity with proinsulin), and the fasting proinsulin:insulin ratio in 206 nondiabetic Mexican-American (a high-risk population for NIDDM) and 123 nondiabetic non-Hispanic white (a low-risk population for NIDDM) participants in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Mexican-Americans had significantly higher fasting and 2-h proinsulin and insulin levels but similar fasting proinsulin:insulin ratios compared with non-Hispanic whites. After statistical adjustment for age, body mass index, waist-to-hip ratio, and glucose tolerance status, Mexican-Americans continued to have higher fasting and 2-h insulin and fasting and 2-h proinsulin concentrations but similar proinsulin:insulin ratios compared with non-Hispanic whites. The fasting proinsulin:insulin ratio was higher in 85 subjects with NIDDM compared with subjects with IGT or normal glucose tolerance (0.31, 0.09, and 0.07, respectively). Thus, nondiabetic subjects from a high-risk population for NIDDM are hyperinsulinemic (using an assay that does not cross-react with proinsulin) and, further, do not secrete more proinsulin relative to insulin itself than do nondiabetic subjects from a low-risk population.

Diabetes Mellitus, Type 2↗
PubMed1991

[Study on screening for primary liver cancer in high risk population of an endemic area].

Positive HBsAg males aged 30-59 years in Qidong were considered a high risk population for primary liver cancer (PLC). A screening study was conducted among 3,958 high risk population which were assigned randomly to a screening group or to a non-screening group. 2,580 persons were screened by alpha-fetoprotein (AFP) once every six months, the incidence rate of PLC was 1,599.38 per 100,000 person-years (PYs), and that in non-screening group with 1,378 persons was 729.39 per 100,000 PYs. Screening survey was also done among 2,332 males aged 30-59 years with negative HBsAg at one-year interval, and the incidence was 128.76 per 100,000 PYs. 26 (86.67%) of 30 PLC patients found in the screening survey were stage I PLCs, but none in 11 out-patients was found in this stage. This study suggests that periodic AFP screening for high risk population is suitable for the high-incidence area, and is one of the effective ways of secondary prevention for PLC.

Adult↗
PubMedDate not supplied

Data assessing the usefulness of screening obstetrical ultrasonography for detecting fetal and placental abnormalities in uncomplicated pregnancy: effects of screening a low-risk population.

To investigate the usefulness of screening in low-risk populations, the authors evaluated the yield of ultrasonography for detecting abnormalities in 678 clinically uncomplicated pregnancies. The yield of ultrasonography in high-risk women who were referred for amniocentesis was remarkably similar to the yield in other women. All four diagnoses of twins were correct, but overall only six of 12 initial ultrasound diagnoses of fetal demise or fetal anomalies were confirmed at delivery. Of the eight major fetal anomalies present at delivery, including two cases of Down's syndrome, three had been detected by ultrasonography; none of the nine minor anomalies had been detected, usually because they were too small or might be detectable only at a later gestational age. Although ultrasonography may have a nearly perfect predictive value for certain anomalies, on average, in this study, positive ultrasonography increased the probability of an adverse outcome of pregnancy from 5.3% to 36%, while a normal ultrasound examination decreased the probability to 4.4%. These data, which emphasize the implications of screening a low-risk population, suggest that recommendations regarding routine screening obstetrical ultrasonography should await sufficiently large controlled trials demonstrating consistent clinical benefit, in terms of reassurance or of providing a baseline for future comparison or in terms of improved outcome at a reasonable cost.

Abnormalities, Multiple↗
PubMed1996

[Screening of high-risk population susceptible to stroke and their characteristics].

High-risk population susceptible to stroke were screened with self-designed scoring method for quantitatively evaluating the risk of stroke in 550,000 frame population in 22 areas with different incidence of stroke during 1990-1993 and its related factors were analyzed by a principal component analysis method. Results showed scoring value correlated positively with probabilities of stroke, which suggested its objectivity and feasibility. The first principal component correlated positively with age, blood pressure, blood sugar, blood cholesterol, body mass index, ect., which reflected the characteristics of high risk population susceptible to stroke, and 71.43% of those with stroke were in the first principal component class. The proportion of the population with the first principal component correlated positively with the incidence of stroke in the area, therefore, stroke prevention should be focused on such population.

Adult↗
PubMed1992

Two-year survey of the incidence of Lyme borreliosis and tick-borne encephalitis in a high-risk population in Sweden.

A survey was made over a two-year period (September 1987 to August 1989) of a population living in an area endemic for Lyme borreliosis and tick-borne encephalitis in Sweden. For each patient a blood sample was collected and a questionnaire completed annually. All sera were tested for an antibody response to Borrelia burgdorferi in an EIA using sonicated antigen and for an antibody response to the tick-borne encephalitis virus using an EIA and a haemagglutination inhibition test. Antibodies to Borrelia burgdorferi and tick-borne encephalitis virus were detected in 89 (25.7%) and 40 (11.6%) respectively of 346 samples collected in August 1987. In the first year of the study 14 of 303 subjects (4.6%) developed Lyme borreliosis and in the second year 9 of 277 subjects (3.2%). A significant increase in the antibody titre for Borrelia burgdorferi was seen in 14 of 303 (4.6%) subjects in the first year and 8 of 277 (2.9%) subjects in the second year. An earlier episode of Lyme borreliosis or an elevated antibody titre did not seem to protect against reinfection. One case of tick-borne encephalitis was seen each year. Seroconversion for tick-borne encephalitis virus was found in 3 of 258 (1.2%) subjects in the first year and 5 of 211 (2.4%) in the second year, excluding subjects who had undergone successful immunisation or had earlier been hospitalised for tick-borne encephalitis. The study thus demonstrated a high yearly incidence of tick-borne infections in a population at risk.

Adolescent↗
PubMed1988

Influence of human immunodeficiency virus antibody testing on sexual behaviour in a "high-risk" population from a "low-risk" city.

A survey was undertaken of homosexual and bisexual men in Brisbane to establish whether knowledge of their human immunodeficiency virus (HIV)-antibody status had influenced any sexual behaviour that was likely to spread HIV type 1 (HIV-1). Of the 318 respondents, 123 respondents knew their HIV serological status, and 13 of these were HIV seropositive. Of the 195 respondents who previously had not been tested, 10 individuals proved to be HIV seropositive. Eighty-two per cent of subjects stated that they had reduced their sexual activity because of their awareness of the acquired immunodeficiency syndrome (AIDS); this reduction was equally common among those who had or had not previously had their HIV serological status checked. Anal intercourse was practised most frequently by those subjects who were HIV seropositive and were not aware of it; nevertheless, unprotected anal intercourse was common among subjects who knew their HIV serological status, including those who knew that they were HIV seropositive. Eighty-nine of 208 subjects who were practising anal intercourse had never used a condom. Usage of a condom was marginally more common among those subjects who previously had been tested for the presence of HIV antibodies (P = 0.06), and this was particularly so for those subjects who knew that they were HIV seropositive (P less than 0.01). Condom usage was no more common among those subjects who knew that they were HIV seronegative, when compared with those subjects who did not know their status. These data show that knowledge of a negative HIV-antibody test-result has no substantial association with safer sexual behaviour and suggest that whereas targeted information programmes have had some impact on behaviour in high-risk groups in Brisbane, by the end of July 1986, these programmes had not yet resulted in safer sexual practices by the majority of homosexual and bisexual men.

AIDS Serodiagnosis↗
PubMed1998

Detection of fetal congenital heart disease in a low-risk population.

Our purpose was to evaluate the efficacy of level two ultrasound screening for the detection of congenital heart defects (CHD) in a low-risk population by using three standardized cuts. Within a period of four years a total of 6727 pregnant women of a low-risk population undertook several ultrasound examinations on the basis of screening for fetal malformations. All ultrasound examinations were performed by three experienced doctors. At every single scan three standardized cuts (apical and lateral four-chamber view, crossing over of the great arteries) were obtained in order to detect congenital heart defects. Of 87 CHDs (1.33 per cent of the examined women) 39 (43.8 per cent) were diagnosed prenatally. The detection rate was 10/48 (20.8 per cent) in the presence of VSD, ASD2 or combined ASD2 + VSD, the detection rate was 29/39 (74.3 per cent) in the presence of other forms of congenital heart disease. None of the 38 missed cases in the first group but three of the ten missed CHDs in the second group had emergency neonatological problems. Aneuploidy and/or other malformations existed in 22/87 cases of CHD. The obstetrical management was changed in nearly all cases after the diagnosis of a CHD. Twenty-two women opted for termination of pregnancy because of additional fetal malformations or chromosomal defects. Five women were transferred prenatally to a tertiary centre for neonatal cardiac surgery. Ten deliveries were performed in the presence of a neonatologist. Good detection rates for CHD can be achieved in a low-risk population on the basis of level two ultrasound screening by using the above mentioned three cuts and thus, the perinatal mortality and morbidity can be improved.

Abnormalities, Multiple↗
PubMed1997

Predictive value of Doppler umbilical artery velocimetry in a low risk population with normal fetal biometry. A prospective study of 2016 women.

OBJECTIVE: To assess the predictive value of Doppler umbilical artery velocimetry in a low-risk population with normal fetal biometry. STUDY DESIGN: Multicenter prospective study in 17 hospitals with prenatal clinics in France. Two thousand sixteen women who, before 28 weeks gestation were defined as at low risk after routine consultation and after ultrasound. Doppler umbilical artery velocimetry was performed between 28 and 34 weeks gestation. Confounding factors were used to perform multivariate regression. RESULTS: 1903 cases were analysed and 192 (10.1%) had an abnormal Doppler Resistance Index (RI). The abnormal Doppler group contained a significantly higher frequency of severe and moderate small for gestational age infants (SGA), both severe and moderate with a sensitivity of 25.5 and 18.8% respectively. There was no difference in hypertensive disorders or criteria of fetal distress. Mean birth weight was very significantly lower in the abnormal group (162 g). Birth weight was very significantly linked to RI after taking into account confounding variables in the multiple linear regression model (continuous relationship). After multiple logistic regression, the odds ratio associated with an abnormal Doppler result, adjusted for all the confounding factors, was 2.3 (95% CI 1.5-3.7) for moderate SGA and 3.5 (95% CI of 1.8-7.1) for severe SGA. CONCLUSION: Low umbilical Doppler RI is predictive with moderate or severe SGA in a low-risk population with normal fetal biometry, even when the information generally available in clinical practice and ultrasound parameters are taken into account. There is a continuous relationship between RI and birthweight. This predictive value cannot, however, lead to an improvement in neonatal health unless effective measures to prevent SGA exist and umbilical Doppler should not be used in low-risk population on a routine basis.

Birth Weight↗
PubMed1996

Population risk factors for hospitalization for stroke in Scotland.

BACKGROUND: There is considerable heterogeneity of cerebrovascular disease (CVD) incidence throughout Scotland. We sought to relate this geographical variation to differences in population risk factors. METHOD: A computer search of linked national hospital discharge data was performed. Individuals were selected if they had been coded with a diagnosis of CVD (ICD-9 430-438), 1984-1986. Age-sex specific rates were correlated to deprivation score and estimated population risk factors for the 22 local government districts of the Scottish Heart Health Study (1984-1986). RESULTS: Men were more commonly admitted in all districts except one, with an overall male:female ratio of 1.43 (P < 0.0001). Rates for men were significantly higher in populations with elevated mean diastolic blood pressure, greater mean alcohol consumption, and where fewer men ate fruit. The most significant associations of male CVD hospital admissions were with population density and deprivation. A similar pattern was found for women, where CVD was significantly associated with elevated diastolic blood pressure, more smokers and fewer non-smokers, and fewer eating fruit. Again rates were higher in densely populated, deprived districts. Multiple linear regression identified the proportion for men. Sex difference was explained by vitamin C intake. CONCLUSION: Geographical variation in CVD rates in Scotland is related to identifiable population risk factors for atherosclerosis and urban environment.

Adult↗