Relationship between socioeconomic status and ischaemic heart disease in cohort and case-control studies: 1960-1993

BACKGROUND

Much of the information on the relationship between socioeconomic status (SES) and ischaemic heart disease (IHD) comes from ecological, cross-sectional and longitudinal mortality studies. Such studies may present methodological problems which affect cohort studies and case-control studies to a lesser degree.

METHODS

A systematic review was conducted into the relationship between SES and IHD, as reported by cohort and case-control studies in which SES had been measured by education or occupation. A bibliographic search, covering the period 1960-1993, was carried out using Index Medicus, MEDLINE, Sociological Abstracts, Social Scisearch and the references cited in papers identified in such databases. Finally, 34 studies were selected, with data being extracted separately by two reviewers working independently. Where differences of opinion arose, these were resolved by discussion between the two. Multiple linear regression analysis was used to identify determinants of inter-study heterogeneity.

RESULTS

Risk of IHD was inversely related to educational level in the period 1982-1993. There was a lower risk of IHD among manual workers versus non-manual workers until approximately 1970; thereafter the relationship became inverted. The odds ratio for IHD in manual workers rose progressively over the period 1960-1993, something that could not be explained by study design, study size, study country or control for confounding factors. Education- and occupation-related differences in risk of IHD affected all SES levels.

CONCLUSIONS

These findings agree with those yielded by ecological, cross-sectional and longitudinal mortality studies, although they cannot be extrapolated to women, non-white ethnic groups, or developing countries. The inversion of the relationship between SES and IHD, and the increase in socioeconomic differences in IHD in recent years suggest that the problem is potentially controllable and that the necessary policies should be implemented as a matter of urgency.

Occupational exposure to ionising radiation and mortality among workers of the former Spanish Nuclear Energy Board

OBJECTIVES

Firstly, to ascertain whether mortality among workers of the former Spanish Nuclear Energy Board (Junta de Energía Nuclear-JEN) was higher than that for the Spanish population overall; and secondly, if this were so, to ascertain whether this difference was associated with exposure to ionising radiation.

METHODS

A retrospective follow up of a cohort of 5657 workers was carried out for the period 1954-92. Cohort mortality was compared with that for the Spanish population overall, with standardised mortality ratios (SMRs) adjusted for sex, age, and calendar period. Also, Poisson models were used to analyse mortality from lung cancer in the cohort by level of exposure to ionising radiation.

RESULTS

Workers' median and mean cumulative exposures were 4.04 and 11.42 mSv, respectively. Mean annual exposure was 1.33 mSv. Excess mortality due to bone tumours was found for the cohort as a whole (six deaths observed; SMR 2.95; 95% confidence interval (95% CI) 1.08 to 6.43). Among miners, excess mortality was found for non-malignant respiratory diseases (SMR 2.94; 95% CI 2.27 to 3.75), and for lung cancer bordering on statistical significance (SMR 1.50; 95% CI 0.96 to 2.23; P = 0.055). Relative risks of dying of lung cancer from ionising radiation in the dose quartiles 2, 3, and 4 versus the lowest dose quartile, were 1.00, 1.64, and 0.94, respectively.

CONCLUSIONS

Excess mortality from lung cancer was found among JEN miners. Nevertheless, no clear relation was found between mortality from lung cancer and level of exposure to ionising radiation in the JEN cohort. Continued follow up of the cohort is required to confirm excess mortality from bone tumours.

[Food and nutrient consumption in Spain in 1940-1988 (and II). Comparative study of the main sources of information on food consumption]

BACKGROUND

This paper has two objectives. The first is to examine the consistency of the main nutritional studies carried out in Spain over the last fifty years. The second is to use these studies to describe the changes in the Spanish diet over this period and to characterize the present dietary pattern.

MATERIAL AND METHODS

We have used three types of studies. First, food balance sheets elaborated by Barbancho, FAO, OECD and the Department of Agriculture. Second, surveys on the foods purchased by population groups, in particular the household budget surveys, and the "panel de consumo alimentario" from the Department of Agriculture. Third, food consumption surveys from Catalonia, Vasque Country, Murcia, Madrid, and Reus.

RESULTS

Protein, lipid and total caloric intake have increased over the last fifty years. Carbohydrate intake has been stable. Caloric intake from lipids has increased, caloric intake from protein has been stable and that from carbohydrates has decreased. All studies are consistent in that, from 1980 onwards, caloric intake from protein has been 12.5-16.7%, caloric intake from carbohydrates has been 39.3-48.1%, and that from lipids has been 36.6-46.0%. The monounsaturated/saturated ratio has been 1.2-1.7 and the polyunsaturated/saturated ratio 0.4-0.7. All data sources show a high consumption of foods typical of the Mediterranean diet, in particular fruit, vegetables, fish and vegetable oil, rich in unsaturated fats. Consistency among data sources is higher when data are expressed as percentage of total caloric intake than when they are expelled in absolute quantities.

CONCLUSIONS

All data sources suggest that the Spanish diet has changed with the economic development, but it still keeps most of the characteristics of the Mediterranean diet.

Economical saving due to prophylaxis in the prevention of surgical wound infection

The objective was to know the principal risk factors that influence in the development of surgical would infection, and the economical saving achieved with the control of a single variable, that is, right prophylaxis. A prospective study was carried out at the Traumatology Department of La Paz Hospital. A total of 5260 patients operated during 1990-1993 are included. Active epidemiological surveillance was used to check patients; logistic regression was used in the multivariant analysis. The principal risk factors found were: immunodeficiency (OR = 8.67), incorrect healing (OR = 14.42), reoperated patient (patients who needed more than one surgical procedure while they are admitted; reoperations) (OR = 3.57), type of surgery (OR = 4.71) and wrong prophylaxis (OR = 6.36). Making constant all the variables except for prophylaxis, we calculated the percentage of infections prevented by a right prophylaxis, and the cost was calculated starting from the number of extra days of infection. The number of infections prevented during the four years was 310, saving a total of 194 million pesetas (1.5 million dollars), due to right prophylaxis. Cost-benefice ratio = 1/17. We consider of special importance to control this manipulable risk factor, in order to avoid the development of infections.

Interference assessment of yellow fever vaccine with the immune response to a single-dose inactivated hepatitis A vaccine (1440 EL.U.). A controlled study in adults

The objective of this open, controlled clinical trial was to assess whether Yellow Fever (YF) vaccine would interfere with one single dose of an inactivated hepatitis A (HAV) vaccine 1440 El.U. when they are administered simultaneously. One hundred and ten healthy adults (24 +/- 4 years old, 65% females) were included and randomized to receive one single dose of HAV vaccine (Group 1) or HAV vaccine plus YF vaccine (Group 2). All subjects received a booster dose of HAV vaccine (month 6). Anti-HAV antibodies were measured (ELISA method) at screening and at months 1, 6 and 7. One month after the first inoculation, the seroconversion rates and geometric mean titers for anti-HAV were 98% and 275 mIU ml-1 in Group 1 and 100% and 239 mIU ml-1 in Group 2. After the booster dose all vaccinees had become seropositive. Administration of YF vaccine did not alter the safety profile of HAV vaccine. These results indicate that simultaneous administration of YF vaccine does not interfere with the immune response to HAV vaccine (1440 El.U.) in young healthy adults.

[Food and nutrient consumption in Spain in the period 1940-1988. Analysis of its consistency with the Mediterranean diet]

BACKGROUND

Not enough information is available regarding Spanish alimentation from the Civil War up to the present. Furthermore, there are some evidence that the Spaniards are leaving behind their traditional, healthy Mediterranean diet. The aim of this study was therefore to describe the food and nutrient intake trends of the Spanish population from 1940-1988 and establish to what extent the pattern of the Mediterranean diet has been maintained.

METHODS

New food balance sheets for the Spanish population have been elaborated using all the information available and consistently applying the methodology of the European Union over the period from 1940-1988.

RESULTS

Total caloric intake and that of all the macronutrients increased over the study period although this increase was greater after 1960. The contribution of lipids to total caloric intake has increased (30% in 1960-1968 and 42% from 1980-1988), protein contribution has remained the same (13% 1960-1968 and 13% 1980-1988) and carbohydrate intake has decreased (58% from 1960-1968 to 45% from 1980-1988). These changes are the result of an important increase in the consumption of meat, eggs, milk and derivatives. Nonetheless the high intake of fruit and vegetables, fish and olive and seed oils has been maintained. Thus, from 1980-1988 the ingestion of monounsaturated/saturated fatty acids and polyunsaturated/saturated fatty acids was 1.3 and 0.5, respectively.

CONCLUSIONS

The first systematic reconstruction of the alimentary and nutritional history of the Spanish population over the last fifty years has been carried out. The Spanish diet has undergone typical changes associated with economic development but continues to be consistent with the pattern of the Mediterranean diet. These changes in diet are, however, of worry because of their deviation from optimum nutritional patterns.

[Risk factors for local infection in burns. Multivariate study]

BACKGROUND

Infection, which is the most serious complication in burns has been little studied. There the aim of the present was to study this complication and its risk factors in patients admitted into a Burn Intensive Care Unit.

METHODS

Patients admitted from 1988-1992 were prospectively studied. The characteristics of the patients were systematically collected on admission (i.e. age, body area burned [BAB], previous disease) as were those of the patient's evolution in the Burn Unit (i.e. infection, manipulation, and therapy). Prior to analysis the patients were randomly divided into two groups: a "study" group with 455 patients and a "validation" group of 163 patients. A uni and bivariate descriptive study was performed in addition to a multivariate study by unconditional multiple logistic regression obtaining one predictive and one explicative equation. The former was thereafter validated in a sample of 163 patients.

RESULTS

No significant differences were observed between the two groups which were made up of severely ill patients (20% BAG 2/3 with dermodeep flame burns, mean age of 43 years) with a similar rate of infection 7.2% and 8.6%, respectively. The ethiologic agent was Pseudomonas aeruginosa in both groups. On applying logistic regression a predictive equation of burn infection and the main risk factors of infection were obtained: BAB (between 15-30%, odds ratio of 4, being 15 if BAB > 30%), duration of central catheterization prior to infection (1-15 days, odds ratio of 6, being 31 if it is longer than 15 days) and preinfection stay (between 15-30 days, odds ratio of 3, being 10 if the stay is longer than 30 days). The validation was obtained on applying the predictive equation to the patients in both groups to calculate the number of infected patients. In both cases the prediction was correct.

CONCLUSIONS

The main risk factors of burn infection are: body area burned, central catheterization and preinfection hospital stay. The equation which adequately predicts the probability of infection based on the characteristics of the burned patients is a good tool for reducing the frequency of infections in burned patients.

Analytic epidemiology of clinical urinary tract infection in spinal cord injury

The authors studied all patients (121) who were admitted to the National Paraplegic Center of Toledo, during a 6-month period, with spinal cord injuries (SCI). We obtained a clinical urinary tract infection predictive equation dependent on different risk factors (age, hospitalization time, level of SCI, sex, etc.). It is important to note that the main clinical-UTI risk factors were: (1) age, (2) hospitalization period, and (3) SCI category. We also achieved a mathematical model that we can use when the patient is admitted to this Center (in this case we do not include hospitalization time). This model enables us to predict clinical UTI depending on patient characteristics.

[The seroepidemiology of the hepatitis A virus in children and adolescents]

OBJECTIVE

To know the prevalence of antibodies against hepatitis A virus (anti-HAV) in a population of children and teenagers pertaining to three municipalities of the Autonomous Community of Madrid (CAM).

DESIGN

Cross-study. SITE. The study was conducted in three public schools centers of the municipalities located in the Southeast of the (CAM).

PATIENTS AND OTHER PARTICIPANTS

Students between the ages of 6 and 17 whose parents authorized them to be tested.

MEASUREMENTS AND MAIN RESULTS

The presence of anti-HAV antibodies in the serum of 729 students was investigated. Thirty eight of them presented a positive mark, which indicates a prevalence of 5.34%. In the males, the prevalence was 5.7% and in the females it was 5%.

CONCLUSIONS

The prevalence of anti-HAV antibodies is low in our population, agreeing with the delay in the age that the infection is acquired according to various publications.

[Epidemiological study of fertility in adolescents in the Autonomous Community of Madrid]

OBJECTIVE

The purpose of this study was to research the frequency and distribution of fertility in adolescence and, in looking at different environments within the Autonomous Community of Madrid (ACM), to evaluate the relationship of fertility rates to determined variables of a socio-economic, educational and demographic nature.

DESIGN

An observational crossover study was carried out.

SETTING

Autonomous Community of Madrid.

PATIENTS AND OTHERS PARTICIPANTS

In this study, the specific rate of fertility in adolescents (SRFA) was calculated and the correlation between the SRFA and variables of a socioeconomic, educational and demographic nature were analysed by means of the multiple linear regression method.

MEASUREMENTS AND MAIN RESULTS

We found important differences in the distribution of fertility within the ACM. There was also a positive correlation (p < 0.05) between the SRFA and those variables which expressed the percentages of illiteracy, industrial workers and with the synthetic youth index. A negative correlation (p < 0.05) was found for the percentages of graduates, professionals and technicians, managers and directors and with the synthetic ageing index. We found no correlation with the unemployment index. On applying the multivariant model, the variable that weighed most on fertility was the level of education, which was in our case measured by the percentage of illiteracy.

CONCLUSIONS

We found an uneven spread of adolescents' fertility rates in the Autonomous Community of Madrid. The fertility rates were higher in those boroughs where there was more illiteracy.

[The seroepidemiology of the varicella-zoster virus in children and adolescents]

OBJECTIVE

To know the sero-protection level existing of varicella-zoster virus in a population of children and adolescents from Madrid.

METHODS

To carry out this work we have had a total 560 serum from children and adolescents between 1 and 15 years old. Later to detect the title of antibodies against the varicella zoster virus (IgG VZV), we used enzymo immuno-analysis (PLATEST).

RESULTS

The 96.5% of them were positive. Distributing this percentage in a similar way for every age, we get 100% at 8, 9, 10, 11 and 15 years old; 97.5% at 5, 6, 7, 12 and 13 years; 95% at 14 years old; 92.5% at 4 years old and 85% at 1 years old and 84% at 2 years old.

CONCLUSIONS

The prevalence gradually increases with the age, from 20% at 1 year old to 100% at 15, finding the smallest prevalence in 84% to reach rapidly 100%.

[Hepatitis B vaccination in children and adolescents]

OBJECTIVE

This study's main aim was to investigate the immunogenicity of genetic recombinant vaccine in children and adolescents in Madrid, with the intention of determining the length of protection according to the titer of antibodies. A second aim was that of finding the optimum vaccine dosage, in order to suggest possible courses of action leading to an adequate strategy of vaccination.

DESIGN

Crossover study.

SETTING

Three educational centres in Madrid.

PATIENTS AND OTHERS PARTICIPANTS

1,184 pupils between 5 and 17 years old.

INTERVENTIONS

Each individual was given three doses of Engerix B recombinant vaccine in the deltoid area at 0, 1 and 6 months. The vaccine dosage was 10 micrograms for children under 12 and 20 micrograms for those aged 12 and over.

MAIN MEASUREMENTS AND RESULTS

The pre-vaccination markers were determined. A month after completing the vaccination, the titer of antibodies was quantified using the Abbott laboratories' microenzyme-immunoanalysis technique. The overall seroprotection rate was 98.9%. The MGT of the titer of antibodies was 9,283.2 mUI/ml. The seroprotection rates were similar among children under 12. The rates were also similar among those who were 12 or over, with titers of antibodies showing significantly higher in the children aged 12 or over.

CONCLUSIONS

Given the good results obtained, we consider that the children will be protected for about 10 years. We suggest that all children and/or adolescents should be vaccinated as a means of controlling Hepatitis B. The recommended dosage for children under 8 is 10 micrograms and for those aged 8 and over, 20 micrograms.

[The immunogenicity of the vaccine against the HBV in the mentally retarded]

Our group carried out during 1989 a serological cross sectional study in 1,024 mentally handicapped patients (231 with Down's syndrome [DS] and 793 affected with other mental disturbances [OMD]), educated in seven institutions of the Madrid region. Those patients with negative HBsAg and anti-HBc markers were considered vaccination susceptible individuals. This group was constituted by 546 individuals. The regime of vaccination used was 0-1-6 m, and the dose, 20 micrograms i.m. The present study makes an evaluation of the postvaccine serologic results one month after the third dose. It was considered the age, sex and if he or she suffers from Down's syndrome or not. Corresponding with these variables the seroconversion rate (percentage of patients with greater than or equal to 10 IU/l of anti-HBs) was determined as well as the geometric mean titer (GMT) of antibodies. The seroconversion rate was 97.1% in the group affected with DS and 95.5% in the group with OMD, not being this difference statistically significant. There is not also significant association with regard to the sex, being the seroconversion rate in males (94.7%) and females (97.6%) very similar. However, it is significant difference between the mean age of the "responders" to the vaccine (24.6 years of age) and that of the "non responders" (33.3 years of age) (p less than 0.001). Thus, the age exerts a negative influence in the response to the vaccination. The titer of anti-HBs antibody, expressed using the GMT, has significant association with the sex (p less than 0.001) but not with the type of mental disturbance.(ABSTRACT TRUNCATED AT 250 WORDS)

[Seroprotection against hepatitis A, measles, rubella, and parotiditis in an urban school population]

BACKGROUND

To find out the presence of hepatitis A antibodies (anti-HA) in an urban population of Madrid, age ranging from 6 to 18 years. At the same time, the immunity level is evaluated with respect to measles, rubella and mumps in a sub-group aged between 6 and 13 years old.

METHODS

The study was carried out in two schools population of the north area of Madrid.

RESULTS

Anti-HA prevalence in the whole population under study (707 subjects) was of 6%; a direct correlation was observed between prevalence and age. With respect to the seroprotection study against measles, rubella and mumps, 81% out of the 385 vaccinated subjects is protected against the three viruses. Seroprotection rate is of 79% if this is evaluated with respect to the total 6-13 age group under study (458 subjects).

CONCLUSIONS

The results of anti-HA prevalence obtained in the eldest groups reveal that a high percentage of the study population aged 17 (92%) and 18 (84%), is anti-HA negative, which means that they might be susceptible to the infection when reaching the adult age. 21% of the school age group studied with respect to measles, rubella and mumps is seronegative to some of the three viruses. Considering the above results, it appears that it could be interesting to evaluate whether the administration of a booster dose to children in school age would enable to reduce the number of unprotected subjects in the referred ages.

Adjusting risk factors in spontaneous abortion by multiple logistic regression

A cross-sectional case-control study was performed to identify some obstetric and gynaecologic factors that can influence spontaneous abortion. Statistical and epidemiologic analyses were done by multiple logistic regression to adjust OR through the beta coefficient. A dicotomized outcome variable, representing spontaneous abortion, and different independent variables, representing distinct medical factors, were designed. The analysis was carried out with a personal computer and an appropriate statistic package. The variables representing age over 35 and previous spontaneous abortions were shown to be risk factors, adjusted for the rest of variables. The variables representing parity and late menarcheal age lost significance when they were adjusted with multiple logistic regression.

[Epidemiological study and development of dental caries in Madrid students]

It has been done an epidemiologic study about dental caries prevalence in a school population in Madrid. We have studied 3,608 schoolchildren. Total caries prevalence was 53.4%, according other authors. Caries is more frequent between ten years children. We also observed low prevalence in the third year of the study.

[An epidemiological study of tuberculous infection]

We have the stage (or condition) of the tuberculous infection in a groups of 1,450 Schoolchildren aged between 6 and 13 years living in Madrid during the school-year 1988/89. For this we used the PPD-RT 23 tuberculin applying 2UT and considering as positive those reactions which were equal or greater 10mm. The prevalence of the tuberculous infection was 1.47% for children aged 6 years and acquire 4.3% for those aged 13 years with greater risk of 3.02 to acquire the infection in the children aged of thirteen in opposition with those of six years. There are no significant statistical significant statistical differences between boys and girls, nor between private and public colleges. We also found that the annual increment of the infection for the vaccinated-children was of 0.14%, while in no vaccinated it was of 0.64%, being of 0.41% for the whole group. The finally we emphasized the existence of a clear increment of the tuberculous infection related to age-group, being the risk of infection greater in no-vaccinated children aged of 13 and from the other part the necessity to amplify the time duration of this type of studies in order to calculate the RAI in Madrid.

[Conventional and analytic morphometry using the IBAS-1 computer in experimental Trypanosoma b. brucei infection]

A comparative morphometrical study of the experimental infection with T. b. brucei was realized using the conventional method and the IBAS-1 analytic computer. The studied strain of T. b. brucei was preserved during 10 years in laboratory conditions, through inoculations from mice to mice. The effect of a low dose of suramin upon the percentage of different morphological forms of the parasite was analysed and compared with the untreated lots. Certain differences could be appreciated in the results of the two methods of morphometrical studies. The presence of posteronuclear, multinuclear and "stumpy" dividing forms was confirmed in our study. The administration of low doses of suramin produces a serious increase of the number of the dividing, multinuclear and "stumpy" forms.

[Persistence of pleomorphism and the presence of multinuclear forms in experimental infection with T.b. brucei]

Thirty white male mice SWISS ICO NMRI (IOPS) were inoculated intraperitoneally with blood-forms of T.b. brucei of a strain belonging to the Laboratory of Parasitology of the Medicine Faculty of the U.A.M. (Autonom University of Madrid). This strain was preserved during 8 years through inoculation from mice to mice. This strain was received from the Pasteur Institute from Paris. Once infected the mice were submitted to a controle through GIEMSA coloured smears. The various blood-forms registered during the experimental infection were carefully measured and also their proportional presence during the observation. We could appreciate an augment of the Slender forms following the progress of the infection and the apparition of the Stumpy at 48 hours after the inoculation as well as the multinucleate forms. Stumpy forms in division were also observed.