Risk factors and prevalence of coronary heart disease in Puerta Rico

Early-Life Conditions, Rapid Demographic Changes, and Older Adult Health in the Developing World

The demographic transition of the 1930s-1960s dramatically improved life expectancy in some developing countries. Cohorts born during this time are increasingly characterized by their survivorship of poor early-life conditions, such as poor nutrition and infectious diseases. As a result, they are potentially more susceptible to the effects of these conditions at older ages. This study examines this conjecture by comparing obesity, diabetes, and hypertension in older adults born in the beginning portion of the 1930s-1960s across different mortality regimes using a subset of harmonized cross-national data from seven low- and middle-income countries (RELATE, n = 16,836). Using birthplace and height as indicators of early-life conditions, the results show (1) higher prevalence of obesity and diabetes and higher likelihood of obesity, diabetes, and hypertension in middle-income countries, but (2) no convincing evidence to indicate stronger effects of early-life conditions on health in these countries. However, shorter adults living in urban areas were more likely to be obese, indicating the overall importance of early-life conditions and the potential negative impact of urban exposures during adulthood. Obesity results may foreshadow the health of future cohorts born in the later portion of the 1930s-1960s as they reach older ages (60+).

Diabetes mellitus in North West Ethiopia: a community based study

BACKGROUND

Diabetes mellitus is recognized as one of the emerging public health problems in developing countries. However, its magnitude has not been studied at community levels, making the provision of appropriate services difficult in such countries. Hence, this study aimed to compare the magnitude and associated risks of diabetes mellitus among urban and rural adults in northwest Ethiopia.

METHODS

A cross-sectional population based survey was performed using the WHO STEPwise method on adults aged 35 years and above. A multistage cluster random sampling strategy was used to select study participants from urban and rural locations. Fasting blood glucose levels were determined using peripheral blood samples by finger puncture. Prevalence was computed with a 95% confidence interval for each residential area. Selected risk factors were assessed using logistic regression.

RESULTS

The prevalence of diabetes mellitus among adults aged 35 years and above was 5.1% [95% CI: 3.8, 6.4] for urban and 2.1% [95% CI: 1.2, 2.9] for rural dwellers. The majority (69%) of the identified diabetic cases were not diagnosed prior to the survey. The highest proportion (82.6%) of the undiagnosed cases was noted among the rural population and 63% among the urban population. Family history of diabetes (AOR = 5.05; 2.43, 10.51), older age (AOR = 4.86; 1.99, 11.9) and physical inactivity (AOR = 1.92; 1.06, 3.45) were significantly associated with diabetes mellitus among the urban population. Alcohol consumption (AOR = 0 .24, 0 .06, 0.99) was inversely associated with diabetes mellitus in rural areas.

CONCLUSION

The prevalence of diabetes mellitus is considerably high among the urban compared to the rural population. Diabetes is largely undiagnosed and untreated, especially in rural settings. Appropriate actions need to be taken to provide access to early diagnosis and treatment in order to reduce associated complications.

Lifetime risks of cardiovascular disease

BACKGROUND

The lifetime risks of cardiovascular disease have not been reported across the age spectrum in black adults and white adults.

METHODS

We conducted a meta-analysis at the individual level using data from 18 cohort studies involving a total of 257,384 black men and women and white men and women whose risk factors for cardiovascular disease were measured at the ages of 45, 55, 65, and 75 years. Blood pressure, cholesterol level, smoking status, and diabetes status were used to stratify participants according to risk factors into five mutually exclusive categories. The remaining lifetime risks of cardiovascular events were estimated for participants in each category at each age, with death free of cardiovascular disease treated as a competing event.

RESULTS

We observed marked differences in the lifetime risks of cardiovascular disease across risk-factor strata. Among participants who were 55 years of age, those with an optimal risk-factor profile (total cholesterol level, <180 mg per deciliter [4.7 mmol per liter]; blood pressure, <120 mm Hg systolic and 80 mm Hg diastolic; nonsmoking status; and nondiabetic status) had substantially lower risks of death from cardiovascular disease through the age of 80 years than participants with two or more major risk factors (4.7% vs. 29.6% among men, 6.4% vs. 20.5% among women). Those with an optimal risk-factor profile also had lower lifetime risks of fatal coronary heart disease or nonfatal myocardial infarction (3.6% vs. 37.5% among men, <1% vs. 18.3% among women) and fatal or nonfatal stroke (2.3% vs. 8.3% among men, 5.3% vs. 10.7% among women). Similar trends within risk-factor strata were observed among blacks and whites and across diverse birth cohorts.

CONCLUSIONS

Differences in risk-factor burden translate into marked differences in the lifetime risk of cardiovascular disease, and these differences are consistent across race and birth cohorts. (Funded by the National Heart, Lung, and Blood Institute.).

Metabolic syndrome in an Hispanic population–cardiovascular complications

The metabolic syndrome (MetS) is presently one of the main medical problems in developing countries. This syndrome was studied in Puerto Rico at the Cardiovascular Center of Puerto Rico and the Caribbean with emphasis on understanding the cardiovascular complications.

The medical records of patients admitted between 1999 to 2005 were evaluated for three or more MetS diagnostic criteria.

One hundred and seventy-three patients met the consensus criteria of metabolic syndrome (MetS). The mean age of those diagnosed with MetS was 60 years of age. Fifty-seven percent were males and 42 percent females. The mean body mass was 30 kg/m. The ejection fraction was found to be subnormal ( 49±8%) and the end systolic dimension of the left atrium was increased ( 45±10 mm) in comparison to a group of diabetic patients without MetS used for comparison. The incidence of atrial fibrillation was found to be 16% higher in the MetS group than in the comparison group.

The number of cases of metabolic syndrome recorded within the Hispanic population of Puerto Rico showed a higher incidence of atrial fibrillation without ventricular tachycardia. This is thought to be as a result of the abnormal left ventricular and atrial function.

Blood pressure and hypertension in an American colony (Puerto Rico) and on the USA mainland compared, 1886-1930

We compare blood pressure and hypertension between adult men on the USA mainland and in Puerto Rico born during 1886-1930 to test hypotheses about the link between cardiovascular health and large socioeconomic and political changes in society: (a) 8853 men surveyed in Puerto Rico in 1965 and (b) 1449 non-Hispanic White men surveyed on the mainland during 1971-1975. Systolic and diastolic blood pressure and hypertension were regressed separately on demographic and socioeconomic variables and cardiovascular risk factors. Mainland men not taking anti-hypertensive medication showed statistically significant improvements in systolic blood pressure and hypertension at the beginning of the century and men in Puerto Rico showed improvements in diastolic blood pressure but only during the last two quinquenniums. An average man born on the mainland during the last birth quinquennium (1926-1930) had 7.4-8.7 mmHg lower systolic blood pressure and was 61% less likely to have systolic hypertension than one born before 1901. On average Puerto Rican men born during 1921-1925 had approximately 1.7 mmHg lower diastolic blood pressure than men born before 1901. Analyses of secular trends in cardiovascular health complements analyses of secular trends in anthropometric indicators and together provide a fuller view of the changing health status of a population.

Acculturation to Western society as a risk factor for high blood pressure: a meta-analytic review

OBJECTIVE

A number of studies have documented that acculturation to western society is related to an increase in blood pressure (BP). Although there is evidence that higher socioeconomic status appears related to better cardiovascular health, increasing acculturation to western society appears related to worse cardiovascular health. The purpose of this meta-analysis was to investigate the association between acculturation and BP.

METHODS

Literature searches yielded 125 relevant research manuscripts, which were coded by teams of two independent raters. This study was conducted in 2003 and 2004, and research databases such as MEDLINE and PsychINFO were searched through 2004. Measures of association (effect sizes) were extracted for both systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings. Random effects models were used to analyze the resulting data.

RESULTS

The overall effect sizes associated with acculturation were 0.28 for SBP and 0.30 for DBP, with increasing acculturation to western society related to higher BP. More acculturated individuals had an average of 4 mm Hg higher BP than less acculturated individuals, which is similar to the effect sizes of known risk factors for high BP such as diet and physical activity. The effects of acculturation on BP appear to be universal, with similar effect sizes found across all regions of the world. Change in BP due to acculturation was not related to body mass index (BMI) or cholesterol but was related to length of residence in the new culture, with the largest effect sizes seen on initial entry and then decreasing rapidly within the first few years. Sudden cultural changes, such as migration from rural to urban settings, resulted in the largest effect sizes, which finding supports the hypothesis that the stress of cultural change is important role in the acculturation effect.

CONCLUSIONS

Acculturation to western society is associated with higher BP, and the distress associated with cultural change appears to be more influential than changes in diet or physical activity. Future studies would benefit from investigating how cultural change affects health and examining whether some non-Western cultural values and practices are health protective.

Body mass index and mortality: a meta-analysis based on person-level data from twenty-six observational studies

PURPOSE

For this report, we examined the relationships between the conditions of being overweight and obese and mortality from all causes, heart disease, cardiovascular disease, and cancer.

METHODS

We defined the categories of body weight according to level of body mass index, BMI=wt(kg)/ht(m)2, using classifications suggested by the National Institutes of Health and the World Health Organization. These classifications are as follows: "normal weight" is defined as BMI > or = 18.5, but less than 25; "overweight" equals BMI > or = 25, but less than 30; and "obese" individuals have BMIs > or = 30. Our investigation is based on person-level data from 26 observational studies that include both genders, several racial and ethnic groups, and samples from the US and other countries. The database consists of 74 analytic cohorts, arranged according to natural strata including gender, race, and area of residence. It includes 388,622 individuals, with 60,374 deaths during follow-up. We use proportional hazards models to examine the relationships between the BMI categories and mortality, controlling for age and smoking status. We use random-effects models to assess summary relative risks associated with the overweight and obesity conditions across cohorts.

RESULTS

The relative risks among the heaviest individuals for overall death, death caused by coronary heart disease (CHD), and death caused by cardiovascular disease (CVD) are 1.22, 1.57, and 1.48, respectively, when compared with the those within the lowest BMI category. The summary relative risk among the heaviest participants for death from cancer is 1.07.

CONCLUSIONS

We document once again, excess mortality associated with obesity. Our results do, however, question whether the current classification of individuals as "overweight" is optimal in the sense, since there is little evidence of increased risk of mortality in this group.

Wide pulse pressure is an independent predictor of cardiovascular mortality in Puerto Rican men

BACKGROUND AND AIM

Emerging evidence suggests that pulse pressure is an independent predictor of risk for cardiovascular mortality. New studies in diverse populations are needed to further establish the applicability of this finding. Thus, the purpose of this study is to examine the relationship between pulse pressure and cardiovascular mortality in a cohort of Puerto Rican men after 12 years of follow-up.

METHODS AND RESULTS

The Puerto Rico Heart Health Program is a study of coronary disease risk factors in men aged 35-79 years at baseline who had an initial examination during the years 1962-1965. It was attended by 9824 subjects representing 80% of the total age-specific male residents in 4 rural and 3 urban areas of Puerto Rico. Cardiovascular risk factors including systolic and diastolic blood pressures were monitored prospectively. This study includes 9106 men free of overt CHD at baseline who were stratified by quartiles of pulse pressure in mmHg: quartile 1, <or=38, quartile 2, 39-46; quartile 3, 47-56; and quartile 4, >or=57. The odds ratio of cardiovascular mortality was calculated using logistic regression analysis. After adjusting for age, education, smoking status, hypercholesterolemic status, physical activity, diabetic status and mean arterial pressure, we found that those in the highest quartile of pulse pressure (pulse pressure>=57) had significantly higher cardiovascular mortality than those in the lowest quartile (reference group) (OR=1.38 95% CI=1.01-1.88).

CONCLUSION

Our findings showed that a wide pulse pressure is independently associated with cardiovascular mortality in this group of Puerto Rican men.

Prediction of mortality from coronary heart disease among diverse populations: is there a common predictive function?

OBJECTIVES

To examine the generalisability of multivariate risk functions from diverse populations in three contexts: ordering risk, magnitude of relative risks, and estimation of absolute risk.

DESIGN

Meta-analysis of prospective cohort studies.

PATIENTS

Participants from various epidemiological studies.

MAIN OUTCOME MEASURE

Death from coronary heart disease (CHD).

RESULTS

The analysis included 105 420 men and 56 535 women 35-74 years of age and free of CHD at baseline from 16 observational studies with a total of 27 analytical groups. The area under the receiver operating characteristic curve (AUC) was used to judge the ability of the multivariate risk function to order risk correctly. AUCs ranged from 0.60 to 0.80. The AUCs differed significantly between the studies (p < 0.01) but were very similar for different risk functions applied to the same population, indicating similar ability to rank risk for different models. The magnitudes of the relative risks associated with major risk factors (age, systolic blood pressure, serum total cholesterol, smoking, and diabetes) varied significantly across studies (p < 0.05 for homogeneity). The prediction of absolute risk was not very accurate in most of the cases when a model derived from one study was applied to a different study.

CONCLUSIONS

When considered qualitatively, the major risk factors are associated with CHD mortality in a diverse set of populations. However, when considered quantitatively, there was significant heterogeneity in all three aspects: ordering risk, magnitude of relative risks, and estimation of absolute risk.

[Total plasma homocysteine concentrations in Puerto Rican patients with ischemic heart disease]

INTRODUCTION AND OBJECTIVES

In Puerto Rico, it has been established that although coronary disease is the leading cause of death, the population has a lower incidence of coronary disease than in the continental United States. In addition, the severity of the disease is less aggressive in terms of a lower incidence of ventricular tachycardia and sudden death. One factor that could contribute to the lower incidence of coronary disease in Puerto Rico is that our population might have lower total plasma homocysteine concentrations (tHcys) than in the continental United States. Our main objective was to measure tHCys in the Puerto Rican population with atherosclerotic cardiovascular disease (ACD).

METHODS

We randomly measured tHcys concentrations in seventy Puerto Rican patients who were hospitalized at the Cardiovascular Center of Puerto Rico and the Caribbean (UPR Division).

RESULTS

The mean tHCys concentration in these patients is similar to those reported for the Framingham study when adjusted by age (11.2 vs. 11.8 micromol/l). In the Puerto Rican population, males had a higher tHcys concentration than females (11.7 vs 9.5 micromol/l, p = 0.07). In addition, we did not see an increase of tHcys concentrations in diabetic patients when compared with non-diabetics (10.1 vs. 11.2 micromol/l, p = 0.74). We did not see a direct correlation between tHcys concentrations and heart condition as measured by coronary angiography (normal = 11.1 micromol/l, light = 10.5 micromol/l, moderate = 10.9 micromol/l, severe = 10.5 micromol/l; Kruskal-Wallis = 0.45) either.

CONCLUSION

These results suggest that tHcys concentration is not a good predictor of the seriousness of ACD in the Puerto Rican patient population.

Cross-Sectional Assessment of Laboratory Variables in a Healthy Male Population

The statistical analysis of 29 laboratory variables with five decade age groups shows statistical differences between cigarette smokers and nonsmokers in serum alpha-2 and gamma globulin in fractions over multiple age groups, and hemoglobin, hematocrit, phosphorus, urine reaction, total bilirubin, and WBC in random age groups. Cholesterol level, although having a slightly lower mean and falling off at a later age in nonsmokers, is not statistically different from the smokers. It would appear that cigarette smoking has little effect on most laboratory tests in a large group of healthy males.

Urban-rural differences in 12 year coronary heart disease mortality: the Puerto Rico Heart Health Program

Preliminary observations of the Puerto Rican population in 1965 indicated that the coronary heart disease mortality rate was lower than in the U.S., and that the rate in rural areas might be less than urban ones because of lower levels of cardiovascular risk factors. This prompted a prospective investigation of 8793 urban and rural men, aged 45-64 years. A 12-year mortality study has been completed with almost total follow-up. After excluding those with known coronary heart disease at baseline, age-adjusted rates for coronary heart disease, sudden, and stroke death are 19-37% higher in urban than rural men. Urban men had higher average blood pressure, cholesterol, glucose, and heart rate and were less physically active than rural men. When urban-rural differences for the known risk factors, including education and alcohol intake, are adjusted for by multivariate logistic regression analysis, no remaining significant urban-rural coronary heart disease mortality differential is present. Thus, it appears that variation in identified risk factors could explain the difference in mortality within Puerto Rico. The presence of unidentified protective factors cannot be excluded.

Mortality among Hispanics in metropolitan Chicago: an examination based on vital statistics data

This paper analyzes the mortality of Mexican Americans and Puerto Ricans residing in the Chicago metropolitan area. In a comparison of these two groups with nonHispanic whites in the same area, it was found that Hispanic mortality is unusually low for the two leading causes of death in the mainstream U.S. population. Explanations discussed include underdiagnosis, underreporting of illness, the "healthy migrant" thesis and possible return migration of elderly ill.

Milk consumption, calcium intake, and decreased hypertension in Puerto Rico. Puerto Rico Heart Health Program study

The baseline observations in the Puerto Rico Heart Health Program during 1965-1968 involved blood pressure determinations, other measurements, and a 24-hour dietary recall in 7932 men aged 45-64 years. This extensive data base provided an opportunity to test the hypothesis that low calcium intake is related to increased blood pressure level. Among men without baseline coronary heart disease and not taking antihypertensive medication, there was an inverse relationship between milk consumption and definite hypertension in urban Puerto Rican men and older rural men. When data from all age and area groups had been averaged, a twofold increase in hypertension was found in subgroups who drank no milk compared to those who consumed over 1 quart of milk a day. Similar trends were found when an estimate of total calcium intake from food, principally from milk, was used. With multivariate analysis while known correlates of blood pressure were simultaneously considered, an independent effect persisted between milk consumption and blood pressure. These results appeared to confirm an inverse association between calcium and hypertension. It was still not possible to ascribe a causal relationship between calcium and blood pressure, however, due to the intricate network of covarying food intakes, the factors related to absorption or lack of absorption of calcium, and the possible role that unmeasured social and cultural factors may play in the observed relations.

Ischemic heart disease risk factors after age 50

Previous studies have suggested that the predictive power of the three major risk factors for ischemic heart disease (hypertension, hypercholesterolemia, and cigarette smoking) decreases sharply with age. We re-examined this question in a cohort of 3187 adults aged 50-79 with baseline evaluation in 1972-1974 who were followed at least 9 years during a period of a marked decline in national cardiovascular disease mortality. Four-hundred and eighty-three subjects died, 123 of ischemic heart disease. Predictors of outcome were studied separately in younger (age 50-64) and older (age 65-79) groups. After multivariable adjustment for potential confounders using Cox proportional hazards models, cholesterol retained a significant independent predictor of ischemic heart disease mortality at older ages for both men and women. Cigarette smoking and hypertension were significantly related to all-cause but not to ischemic heart disease mortality in this older population. We suggest that the persistence of cholesterol as an independent predictor of fatal ischemic heart disease in old age may reflect the consequences of a shift in risk factor distribution with deferred selective mortality in a cohort with an overall favorable risk factor status.

Diet and its relation to coronary heart disease and death in three populations

Baseline 24-hour dietary recalls from 16,349 men ages 45-64 years who had no evidence of coronary heart disease (CHD) were obtained in three prospective studies: the Framingham Study (859 men), the Honolulu Heart Study (7272 men) and the Puerto Rico Heart Health Program (8218 men). These men were followed for up to 6 years for the first appearance of CHD or death. Men who had a greater caloric intake or a greater caloric intake per kilogram of body weight were less likely to develop CHD manifest as myocardial infarction (MI) or CHD death, even though men of greater weight were more likely to develop CHD. This may reflect the benefit of greater physical activity. Men who consumed more alcohol were less likely to develop CHD, but more likely to die of causes other than CHD, particularly in the Honolulu study. In the Honolulu and Puerto Rico studies, but not in the Framingham study, men who consumed more starch were less likely to develop MI or CHD death. There was an inverse relation between starch intake and serum cholesterol, but it was too weak to explain fully the inverse starch-CHD association. There was also no evidence that the inverse relation between starch intake and incidence of CHD in the Honolulu and Puerto Rico studies was an indirect result of differences in fat intake. While the findings suggest additional areas for research, none of them would lead to an alteration of currently recommended preventive diets that emphasize lowering fat intake, because in isocaloric diets the logical way to balance a decreased fat intake is to increase the consumption of foods containing starch.

Relation of lipids, weight and physical activity to incidence of coronary heart disease: the Puerto Rico heart study

The 2 1/2 year incidence of coronary heart disease was examined in relation to antecedent serum cholesterol and fasting triglyceride levels, physical activity status and relative weight in a cohort of 8,171 urban and rural men 45 to 64 years old participating in the Puerto Rico Heart Program. In this population with a low incidence rate of coronary heart disease, risk of coronary disease was related to serum cholesterol in both urban and rural groups, but this trend was statistically significant only in the urban population. Neither the urban nor the rural population showed a substantial or statistically significant association of serum triglyceride levels with incidence of coronary heart disease. Correlations among relative weight and serum triglyceride and serum cholesterol levels were noted. Despite small differences in incidence of coronary heart disease between urban and rural groups, values for serum cholesterol, triglycerides and relative weight were all significantly higher in the urban men. Only physical activity levels were higher in the rural men. Multivariate analysis, performed to sort out the net effects of these interrelated variables, revealed that serum cholesterol is related to the risk of coronary heart disease even when all variables are taken into account. Low levels of physical activity were significantly associated with a greater incidence of coronary heart disease only in urban men (P less than 0.05). Overweight, which was associated with higher lipid values and less physical activity, was not related to the development of coronary heart disease in either the urban or the rural cohort.

Serum cholesterol and triglyceride concentrations of Finns and Finnish Lapps. II. Interpopulation comparisons and occurrence of hyperlipidemia

Only small differences in serum cholesterol means and somewhat larger, but still modest differences in log(TG) means were observed, when seven Finnish population groups were compared. Semiurban and industrial groups had the highest triglyceride levels. Cholesterol levels tended to be lower in South Finland than in East or North Finland and lowest in semiurban population groups. Between 15-59 years of age, rural Finns of both sexes had higher and after this age lower cholesterol means than the Finns in the other population groups. The highest cholesterol levels below the age of 60 were observed in a rural population group in East Finland. The Finnish Lapps and the rural Finns had nearly identical serum lipid levels in spite of the differences in genetic background and way of life. The serum lipid concentration means were quite similar to those reported from the other Nordic countries, Denmark, Norway and Sweden. The differences between the populations of the Nordic countries are no larger than those observed between the Finnish population groups. However, no population in Scandinavia or elsewhere can confidently be said to have higher serum lipid levels than the Finns. The similarity of the lipid levels observed in different areas in Finland and in the larger Nordic area is remarkable in view of the large differences in the incidence of coronary heart disease and in mortality rates. It is conceivable that part of the variations in disease rates is attributable to differences in the prevalence of hyperlipidemias, although the present study does not prove this hypothesis. Such differences could occur in spite of similarities in the lipid concentration means. Prevalences of hyperlipidemias in Finland are given.

Antecedents of cardiovascular disease in six Solomon Islands societies

Cardiovascular risk factors have been analyzed as part of a combined ethnographic, anthropometric, and medical study of 1390 adult subjects in defined populations representing six Solomon Islands Societies. The six societies, all at low levels of acculturation, differed in habitat, way of life, and exposure to Western civilization. Criteria for ranking the societies in respect to acculturation were developed based on demographic changes within defined populations, secular increase in adult height, length and intensity of contact with Western cultural influences, religious belief, education, availability of medical care, economy, and diet. The six tribal groups were ranked by these criteria as follows: (1) Nasioi, (2) Nagovisi, (3) Lau, (4) Baegu, (5) Aita, (6) Kwaio. Physical health and nutrition were good in all six groups, and clinical evidence of coronary heart disease and atherosclerosis was absent. Serum cholesterol levels were higher at almost all ages and both sexes in the three more acculturated than in the three less acculturated groups. Serum uric acid levels were lower in the more acculturated than in the less acculturated groups. Among adult males in all groups, systolic blood pressure showed no age-related trend while diastolic blood pressure declined with age in the three less acculturated groups. Among adult females systolic blood pressure increased significantly with age in the three more acculturated groups but showed no age trend in the less acculturated. Weight declined with age in all groups. Analysis of electrocardiograms by the Blackburn method showed striking absence of codable abnormalities in all groups and a lower frequency of most abnormalities associated with coronary disease than in any population previously reported.

The differences in serum cholesterol and uric acid levels, and in intrapopulation trends of blood pressure in relation to age between the more and less acculturated groups were found to correlate best with dietary differences, especially in intake of salt, and of tinned meat and fish. The biologic differences noted may represent the earliest antecedents of cardiovascular disease in these societies.

Interrelationship of serum lipids with relative weight, blood glucose, and physical activity

Serum cholesterol, serum glyceride, blood glucose, relative weight, physical activity, percent calories from fat, percent calories from carbohydrate, and polyunsaturated/saturated fatty acid (P/S) ratio were determined in 1780 rural and 4023 urban fasting men aged 45-64 years being followed prospectively to ascertain reasons for the low prevalence of coronary heart disease mortality in Puerto Rico as compared to other countries. Lipid and glucose levels and relative weight were higher and physical activity lower in urban men. Glyceride was positively correlated with cholesterol, glucose, and relative weight, and negatively correlated with physical activity. Cholesterol was positively correlated with glyceride, glucose, and relative weight, and not correlated with physical activity. Percent calories from fat and P/S ratio were significantly higher and percent carbohydrates from starch significantly lower in urban men. These variables taken together were not significant in predicting the differences between urban and rural serum cholesterol or glyceride values. Relative weight was the most significant variable in explaining urban-rural differences in serum glyceride and cholesterol levels. These findings confirm the importance of weight control in dietary management for reduction of serum lipids.

Prevalence of plasma lipoprotein abnormalities in a free-living population of the Central Valley, California

In an epidemiologic study of 1,118 free-living volunteers, aged 25 to 79 (552 male, 566 female) drawn from eight counties of the Central Valley, California, the following determinations were included: a medical history, blood pressure, resting electrocardiogram, plasma total cholesterol and glycerides (following a light, fat-free breakfast), and (when lipids were considered to be elevated) plasma lipoproteins determined by electrophoresis. A subgroup of the entire study population (494 male, 503 female) free of overt diabetes and electrocardiographic abnormalities, and with diastolic blood pressure not above 100 mm Hg, that was considered to be clinically "normal," forms the basis of this report.

Significant sex differences for mean levels of total cholesterol were absent or of small magnitude at all age decades up to and including the seventh. In contrast, glyceride levels for men were significantly higher than for women aged 25-59, and differences were substantial. Beyond the seventh decade, females had higher mean levels of both plasma total cholesterol and glycerides.

The type IV lipoprotein pattern was the most common abnormality (8.6%) within the entire normal population and was 2.7 times as common in men (13%) as in women (4.8%). Type II pattern was less common overall (3.7%) and was more frequent in women than in men. Types III (0.2 to 0.4%) and V (0.2%) were both very uncommon, and type I was not encountered. Results were similar when the entire population (normal and abnormal) was considered.

These findings suggest that sex differences in plasma total-cholesterol level cannot account for the known male preponderance in coronary heart disease within the population studied. Prolonged elevation of plasma glycerides (usually expressed as the type IV pattern) in males during the years when atherogenesis is occurring might account for the sex difference.