Jaime Gofin

Indicators of social class: A comparative appraisal of measures for use in epidemiological studies

Various indicators of social class were compared in a community health survey in Jerusalem in order to appraise their value in detecting associations with health characteristics. Correlations among the indicators and between them and selected health-relevant variables were measured. The results suggested that there was little to choose between the occupational scales tested (an adaptation of the British Registrar-Generals scale, a prestige scale, and a socio-economic status scale) for use as general indicators of social class in epidemiological studies, as the correlations between them were very high and the patterns of their correlations with the health variables were very similar. Correlations with some health variables became weaker when less detailed occupational data were used. Other indicators of social class (education, family income, household crowding, an authority rating and an amenities score) were not strongly correlated with occupation, and there were differences in their associations with the health variables, indicating that conclusions about the relationship between health and social class are not insensitive to the measure used. Despite the discrepancies, the patterns of associations with the health measures were broadly similar for occupational scales, education and income, suggesting that if a single measure is to be used there may for some purposes be little to choose between these major indicators. The fairly low correlations among these different indicators of social class suggest that there may be considerable gains from using more than one measure, so as to increase the chance that an association with social class will be detected, to permit appraisal of independent effects and important interactions between indicators, and to increase the overall explanatory or predictive power of the model. The choice of indicators should be determined by practical considerations and by the conceptual framework with respect to the social-class relationships of the health characteristics under study.

Nonfasting Plasma Total Homocysteine Level and Mortality in Middle-Aged and Elderly Men and Women in Jerusalem

The metabolism of homocysteine, a sulfur amino acid, is at the intersection of two metabolic pathways: transsulfuration and remethylation (1). McCully (2) first proposed that severe hyperhomocysteinemia is related to both atherosclerosis and vascular thrombosis. Recent evidence (3-5) has shown an association between mildly to moderately elevated blood concentrations of total homocysteine and vascular disease (including its coronary, cerebral, and peripheral manifestations). Much of the supporting evidence for this association has been obtained from casecontrol studies; reports of prospective studies of cardiovascular disease, however, are inconsistent (6-12). It remains to be established whether this relation is causal and whether reduction of plasma homocysteine level will decrease risk. Most studies have been done in Europe and North America. Only two recent reportsone from the Framingham Study (13) and one on patients with coronary heart disease in Norway (14)have used total mortality as an end point with which to assess health outcomes associated with a modestly elevated homocysteine level. We addressed the question of this relation in a study of nonfasting plasma homocysteine levels and 9- to 11-year all-cause mortality in a cohort of Jewish men and women 50 years of age and older living in Jerusalem. The study sample is ethnically heterogeneous, consisting mainly of persons from central and eastern Europe, northern Africa, and the Middle East who immigrated in the 1950s and 1960s, as well as those born in Israel. Methods Study Sample The third round of examinations of the Kiryat Yovel Community Health Study took place from 1985 to 1987. A neighborhood sample in western Jerusalem was identified by conducting a household census of dwelling units. All identified residents 50 years of age or older were invited for an interview and examination and were asked to give informed consent to participate (15-17). Data Collection A structured interview, administered by trained interviewers during the afternoon, was followed by an examination that included standardized measurements of blood pressure, anthropometric indexes, 12-lead electrocardiography, and a nonfasting blood sample (16, 17). Biochemical Measurements Blood was drawn into plain Vacutainers (Becton Dickinson, Carlsbad, California) and Vacutainers that contained EDTA; 90% of the samples were taken between 1:00 p.m. and 6:00 p.m. The EDTA tubes were immediately refrigerated for up to 2 to 3 hours until centrifugation. Aliquots were stored at 20 C for 9 to 11 years until they were shipped on dry ice to Boston, Massachusetts, for analysis of homocysteine. Plasma total homocysteine, the sum of protein-bound and free homocysteine, was measured by using high-performance liquid chromatography with fluorometric detection, as described by Araki and Sako (18), except for isocratic column elution. Pooled plasma was used for quality control. The interassay and intra-assay coefficient of variation for this method is less than 5%. Serum glucose level, cholesterol level, thiocyanate level, creatinine concentration, blood urea nitrogen level, and albumin level were measured on a Technicon SMAC (Technicon Instruments Corp., Tarrytown, New York). High-density lipoprotein cholesterol level was measured enzymatically (Laboratoires Biotrol, Paris, France) on a Cobas Bio autoanalyzer (F. Hoffman-La Roche Ltd., Basel, Switzerland). Physical Measurements and Interview Data Blood pressure was measured with a mercury sphygmomanometer (16). Body mass index was computed (17). Participants were asked whether a physician had ever told them that they had diabetes. They were also asked, Is your general health at present very good, good, not so good, poor, or very poor? The first two categories were combined as good health, and the last two categories were combined as poor health. Simple self-appraisals, which are common indexes of general health, are correlated with health ratings on the basis of objective measures and are predictors of subsequent death (19-23). Prevalence of cardiovascular disease was defined as typical angina (24) confirmed by a physician, reported history of heart attack, or reported history of stroke. A food-frequency questionnaire included assessment of the usual intake of fruit, fresh vegetables, and cooked vegetables. Follow-up and Causes of Death Deaths that occurred before April 1996 and the underlying cause of death as coded by the Israel Central Bureau of Statistics (International Classification of Diseases, Ninth Revision [ICD-9] codes) were identified by linkage with the national population registry. Statistical Analysis Skewed distribution of plasma homocysteine level was corrected by natural logarithmic transformation. Mean homocysteine levels, when presented, are geometric unless otherwise specified. Associations of homocysteine level with covariates were assessed by age-adjusted partial Pearson correlations and analysis of variance. Kaplan-Meier survival curves were computed for quintiles of homocysteine level after age adjustment by regression. The main analyses used Cox proportional-hazards regression to model survival according to sex-pooled quintiles of homocysteine level, adjusting for possible confounders. In these models, the outcome variable was time to event. Tests for trend were assessed with the logarithm of homocysteine level introduced as a continuous variable. Uniformity in the association of homocysteine level with survival over time was tested by introduction of time-dependent terms. Differences in hazard ratios between the sexes, age groups (<65 years of age and 65 years of age), and ethnic groups were tested by using multiplication terms. Analyses were implemented by using SPSS (SPSS, Inc., Chicago, Illinois). The population attributable fractionthat is, the proportion of all deaths in the population associated with elevated homocysteine levels (cut-off points used elsewhere [25, 26], 13 and 14 mol/L)was computed as Pe (HR 1)/1 + [Pe (HR 1)], where Pe is the proportion of patients with a plasma homocysteine level of at least 13 mol/L or at least 14 mol/L and HR is the respective hazard ratio computed from Cox models. Results Participant Characteristics All 2303 persons identified in 3434 dwelling units in the Kiryat Yovel community who were at least 50 years of age were invited to participate in our study. The response rate for the original census was 96%. A total of 1948 men and women gave informed consent and agreed to participate (85% response rate). Nonrespondents were similar to respondents with regard to age and sex. Plasma total homocysteine was measured in blood samples obtained from 1788 participants (92% of the total); the 160 participants with missing measurements did not differ significantly from those with no missing measurements with respect to age, reported diabetes, or self-appraised health. Covariate data were incomplete for 77 of the 1788 participants in the multivariate-adjusted models. The age distribution of the study sample is shown in Table 1. The mean age was 64.6 years for men and 64.5 years for women (range for both sexes, 50 to 92 years). Table 2 shows the heterogeneity of the sample with respect to place of birth and level of education. Of the 1788 participants, 13% (n=239) reported having received a physicians diagnosis of diabetes, 16% (n=283) had a history of cardiovascular disease, and 30% had hypertension (defined as systolic blood pressure 160 mm Hg, diastolic pressure 95 mm Hg, or current treatment for hypertension). Distributions of smoking and self-appraised health are shown in Table 2. Nineteen percent of men and 41% of women had a total serum cholesterol level of 6.5 mmol/L or greater ( 251 mg/dL) . The prevalence of obesity (body mass index 30.0 kg/m2) was high (32% in women and 16% in men). Table 1. Plasma Total Homocysteine Levels and Number of Deaths during 9- to 11-Year Follow-up, according to Age at Initial Examination (1985-1987) Table 2. Predictors of All-Cause Death during 9- to 11-Year Follow-up Correlates of Total Plasma Homocysteine Level We examined the relation of plasma homocysteine level to the time that had elapsed since food or drink was last consumed. A weak age-adjusted association (r=0.06; P=0.049) was restricted to women. Homocysteine levels increased with age, were higher in men than in women (Table 1), and were not significantly associated with place of birth or level of education (not shown). The strongest age-adjusted correlations were with serum creatinine concentration (r=0.21 in men and r=0.29 in women; P<0.001). The inverse relation with serum glucose level (r= 0.09 in men [P=0.011] and r= 0.15 in women [P<0.001]) was not affected by the amount of time that had passed since the participants last meal. Age- and sex-adjusted mean homocysteine levels were lower among persons who reported that they had diabetes than among those who did not (1.1 mol/L; P<0.001). Homocysteine levels were 1.1 mol/L higher in men who smoked (P=0.004) than in men who did not smoke and were positively correlated with serum thiocyanate level (r=0.12; P<0.001); these associations were weaker and nonsignificant in women. No significant associations were seen with blood pressure, body mass index, or serum lipid levels. Correlations with intake of fruit, fresh vegetables, cooked vegetables, and total vegetables were weak (r= 0.08 [P=0.045], r= 0.10 [P=0.014], r= 0.04 [P>0.2], and r= 0.10 [P=0.015], respectively, in men; r= 0.06, r= 0.04, r= 0.05, and r= 0.04, respectively, in women [for all comparisons P>0.2]). Participants with poor self-appraised health had higher age-adjusted homocysteine levels than participants in fair health or good health (1.8 mol/L and 1.5 mol/L, respectively, for men [P=0.05] and 1.0 mol/L and 0.9 mol/L, respectively, for women [P=0.2]; P=0.012 in the total sample [sex-adjusted]). Homocysteine Level and Death during 9 to 11 Years of Follow-up Among the 1788 participants,

Health status and mortality in Holocaust survivors living in Jerusalem 40-50 years later.

The long-term health sequelae of the Holocaust were assessed 40–50 years later in the framework of a Jerusalem community health study. Holocaust survivors (N=288, mean age = 67.6 years) and European-born Jews, not exposed to the Holocaust (N=486, mean age = 68.9 years), were studied in 1985–87. Our objective was to compare psychobehavioral factors, clinical variables, and mortality outcomes. The comparisons revealed higher emotional distress scores in female Holocaust survivors than in unexposed women and poorer self-appraised health status in male Holocaust survivors than unexposed men. A 10-year mortality follow-up that terminated in April 1996 showed no significant association with Holocaust exposure. Long-term Holocaust survivors may represent a selective resilient group.

The effect on birth weight of employment during pregnancy.

A study involving 708 women was conducted to determine the effect of employment while pregnant on birth weight. 47.5% of the women were employed and 85.7% of them were employed in the 3rd trimester. 78.6% of the working women held jobs with light physical activity (e.g. clerk secretary professional) 17.6% held jobs with moderate activity (e.g. kindergarten teacher factory worker) and 3.8% held jobs with heavy physical activity (e.g. cleaner). The moderate and heavy physical activity was virtually limited to lower social classes. Women with higher education tended to work and women with high parity tended not to work. There were no differences between employed women and housewives with regard to pregnancy complications however a higher proportion of working women performing heavy activity experienced abnormal conditions. In addition a higher proportion of delivery abnormalities such as vacuum extraction prolonged labor and slight laceration of the perineum occurred in working women. Housewives showed a higher rate (8.1%) of low birth weight of less than or equal to 2500 g than working women (6.0%). Area of birth social class parity pregnancy complications and smoking all affect low birth weight rate and seem to be statistically significant. There was no effect of work on pregnancy or type of delivery found in this study.

Ten-year evaluation of hypertension, overweight, cholesterol, and smoking control: The CHAD program in Jerusalem

Control of hypertension, overweight, hypercholesterolemia, and smoking is a major objective of the CHAD program, a multifactorial cardiovascular risk factor program built into a family practice, which has operated in a neighborhood of western Jerusalem since 1971. By 1975-1976, there was a significantly larger decrease in risk factors in this population than in a neighboring population receiving ordinary medical care. Follow-up based on clinical records of a cohort of 441 people exposed to the program until 1981 revealed that the mean blood pressures decreased and the prevalence of hypertension continued to decrease between 1976 and 1981, from 12.5 to 9.1%. Prevalence of cigarette smoking among people ages 30 years or more also decreased in this period, mainly due to a decrease in heavy smoking, at a time when national surveys provided no evidence of a smoking decrease in this age group. Effects on overweight and cholesterol were not demonstrated during this period. This 10-year evaluation demonstrates the effects of intervention by primary care practitioners in the framework of a community-oriented program.

Work-health relationships in middle-aged and elderly residents of a Jerusalem community

Work-health relationships were examined cross-sectionally in 1886 men and women aged greater than or equal to 50 years in Jerusalem in 1985-1987, in the third round of a multipurpose longitudinal community health study. The main occupational variables were employment status, reasons for not working, and satisfaction with work. Sex and age were controlled in all comparisons. Workers were clearly healthier than nonworkers with respect to general, physical and emotional health, and people who had given up work were less healthy than those still working, whether they had stopped for health reasons, only because of their age, or only for extrinsic reasons (retrenchment or dismissal). Workers who expressed satisfaction with their work were healthier than others, the odds ratio in favour of good general health being 2.4 at 50-64 and 2.5 at greater than or equal to 65 years of age. The associations between job satisfaction and health remained apparent when education and origin were controlled. Multivariate analyses suggested that the associations were not spurious ones attributable to proneness to report both dissatisfaction and ill-health. Job dissatisfaction was not significantly associated with angina pectoris, possible myocardial infarction, or hypertension. Taken at their face value, the findings support the impact of job satisfaction or its determinants on the health of middle-aged and elderly men and women. The associations will be re-appraised in the longitudinal analysis of the study data.