Association of educational achievement with pulsatile arterial diameter change of the common carotid artery: the Atherosclerosis Risk in Communities (ARIC) Study, 1987-1992

Education is strongly inversely associated with common carotid artery intima-media thickness in the Atherosclerosis Risk in Communities (ARIC) Study. The authors extended the ARIC study of preclinical atherosclerosis by evaluating the cross-sectional association of education with common carotid artery elasticity. This study included 10,091 Black and White men and women aged 45-64 years who were free of clinical coronary heart disease and stroke/transient ischemic attack. Arterial elasticity was assessed by pulsatile arterial diameter change (PADC), derived from phase-locked echo-tracking. The smaller the PADC, the stiffer the artery. Education was categorized into grade school, high school without graduation, high school with graduation, vocational school, some college, and graduate/professional school. PADC was directly associated with educational attainment. The mean PADCs, adjusted for age, height, diastolic diameter, systolic blood pressure, pulse pressure (linear and squared), ethnicity, gender, and smoking status, in successively higher education strata were 402 (standard error (SE) 5), 403 (SE 4), 407 (SE 3), 413 (SE 4), 416 (SE 2), and 417 (SE 4) microm (p = 0.007). To the authors' knowledge, this is the first time such an association has been reported. If arterial dilation impairment precedes arterial wall thickening in the atherosclerotic process, as recent studies on endothelial dysfunction suggest, these results indicate that low socioeconomic status may be associated with early arterial pathophysiologic changes-an effect that appears to be mediated by established cardiovascular disease risk factors.

A prospective study of cytomegalovirus, herpes simplex virus 1, and coronary heart disease: the atherosclerosis risk in communities (ARIC) study

BACKGROUND

Conflicting evidence exists implicating infectious disease in the pathological processes leading to coronary heart disease (CHD). The objective of this article is to describe the relationship of previous infection with cytomegalovirus (CMV) and herpes simplex virus 1 to incident CHD in a population-based cohort study.

METHODS

Using a nested case-cohort design from the Atherosclerosis Risk in Communities Study, antibody levels to CMV and herpes simplex virus 1 were determined in serum samples that had been frozen at the baseline examination in participants free of CHD. Determinations were made in those who developed incident CHD (n=221) during follow-up of up to 5 years from baseline and in a stratified random sample of all participants (n=515).

RESULTS

The population with the highest antibody levels of CMV (approximately the upper 20%) showed an increased relative risk (RR) of CHD of 1.76 (95% confidence interval, 1.00-3.11), adjusting for age, sex, and race. After adjustment for additional covariates of hypertension, diabetes, years of education, cigarette smoking, low-density lipoprotein and high-density lipoprotein cholesterol levels, and fibrinogen level, the RR increased slightly. Based on a priori hypotheses, the RR of CHD at the highest antibody levels in individuals with diabetes was particularly large but with wide confidence intervals (RR, 9.2; 95% confidence interval, 1.8-47.0), and the interaction between high levels of antibody to CMV and diabetes was statistically significant (P=.05). There was no association of CHD with the highest herpes simplex virus 1 antibody levels (adjusted RR, 0.77; 95% confidence interval, 0.36-1.62).

CONCLUSIONS

High levels of CMV antibodies are significantly associated with incident CHD. Infection with CMV, particularly in more susceptible disease states such as diabetes, may be an important risk factor for CHD.

[Utility of IgG subclasses in the diagnosis and follow up of hydatidosis]

BACKGROUND

The aim of the study is to evaluate the IgG subclasses for the diagnosis and follow-up of hydatidosis disease.

MATERIAL AND METHODS

82 serum of 50 patients previously diagnosed of hydatidosis disease, were studied. This patients were divided into different groups depending on their symptomatology, and 10 serum of healthy individuals were tested for an indirect hemagglutination, and IgG subclasses were studied in all positive cases by an ELISA.

RESULTS

IgG1 subclass was positive in 81 out of 82 patients. IgG2 and IgG3 subclasses were positive in 94.4% of symptomatic patients, in 100% of patients with calcified cyst or who had had no radical surgery, and in 0% of patients with calcified cyst or who had had radical surgery.

CONCLUSION

IgG1 and IgG4 subclasses can be used together for hydatidosis diagnosis, due to their high specificity and sensibility. IgG4 subclass becomes negative soon if there is a good clinical response by the patient, turns to be positive when there is a disease recrudescence, and keeps positive when residual cyst are left. All this makes IgG4 subclass a good marker in the hydatidosis follow-up.

Anger proneness predicts coronary heart disease risk: prospective analysis from the atherosclerosis risk in communities (ARIC) study

BACKGROUND

Increased research attention is being paid to the negative impact of anger on coronary heart disease (CHD).

METHODS AND RESULTS

This study examined prospectively the association between trait anger and the risk of combined CHD (acute myocardial infarction [MI]/fatal CHD, silent MI, or cardiac revascularization procedures) and of "hard" events (acute MI/fatal CHD). Participants were 12 986 black and white men and women enrolled in the Atherosclerosis Risk In Communities study. In the entire cohort, individuals with high trait anger, compared with their low anger counterparts, were at increased risk of CHD in both event categories. The multivariate-adjusted hazard ratio (HR) (95% CI) was 1.54 (95% CI 1.10 to 2.16) for combined CHD and 1.75 (95% CI 1.17 to 2.64) for "hard" events. Heterogeneity of effect was observed by hypertensive status. Among normotensive individuals, the risk of combined CHD and of "hard" events increased monotonically with increasing levels of trait anger. The multivariate-adjusted HR of CHD for high versus low anger was 2.20 (95% CI 1.36 to 3.55) and for moderate versus low anger was 1.32 (95% CI 0.94 to 1.84). For "hard" events, the multivariate-adjusted HRs were 2.69 (95% CI 1.48 to 4.90) and 1.35 (95% CI 0.87 to 2.10), respectively. No statistically significant association between trait anger and incident CHD risk was observed among hypertensive individuals.

CONCLUSIONS

Proneness to anger places normotensive middle-aged men and women at significant risk for CHD morbidity and death independent of the established biological risk factors.

Seasonal variations of blood pressure and overhydration in patients on chronic hemodialysis

Blood pressure (BP) has a seasonal cycle in the general population and in patients undergoing maintenance dialysis, but the causes remain unclear. We studied the BP measurements recorded at fixed hours three times weekly from 1994 to 1997 in 102 hemodialysis patients. We obtained monthly averages of the following variables: predialysis mean BP, greatest overhydration (OH) estimated by predialysis body weight excess over dry weight, chronic OH estimated by the remaining postdialysis weight excess over dry weight, urea reduction ratio (URR) in dialysis, and monthly means for daylight span and outdoor temperature over the study period. Average BP in the population diminished over the 48-month period, associated with a decrease in chronic OH (r = 0.66; P < 0.0005) but independent of greatest OH. BP and chronic OH presented synchronous seasonal variations, with peaks in late autumn and early winter and troughs in summer. These biological rhythms were inversely related to the seasonal daylight span and outdoor temperature. Both BP and chronic OH periods were synchronous with the daylight annual cycle and preceded the seasonal variations of temperature by 1 month. Multiple regression analysis showed that chronic OH and daylight, but not URR or temperature, had a significant independent association with BP changes. These results show the existence of seasonal variations of BP in dialysis patients that are associated and synchronous with seasonal changes in chronic OH status. Both cycles depend on conditions influenced by the annual daylight span more than by external temperature.

Association of sleep-disordered breathing, sleep apnea, and hypertension in a large community-based study. Sleep Heart Health Study

CONTEXT

Sleep-disordered breathing (SDB) and sleep apnea have been linked to hypertension in previous studies, but most of these studies used surrogate information to define SDB (eg, snoring) and were based on small clinic populations, or both.

OBJECTIVE

To assess the association between SDB and hypertension in a large cohort of middle-aged and older persons.

DESIGN AND SETTING

Cross-sectional analyses of participants in the Sleep Heart Health Study, a community-based multicenter study conducted between November 1995 and January 1998.

PARTICIPANTS

A total of 6132 subjects recruited from ongoing population-based studies (aged > or = 40 years; 52.8% female).

MAIN OUTCOME MEASURES

Apnea-hypopnea index (AHI, the average number of apneas plus hypopneas per hour of sleep, with apnea defined as a cessation of airflow and hypopnea defined as a > or = 30% reduction in airflow or thoracoabdominal excursion both of which are accompanied by a > or = 4% drop in oxyhemoglobin saturation) [corrected], obtained by unattended home polysomnography. Other measures include arousal index; percentage of sleep time below 90% oxygen saturation; history of snoring; and presence of hypertension, defined as resting blood pressure of at least 140/90 mm Hg or use of antihypertensive medication.

RESULTS

Mean systolic and diastolic blood pressure and prevalence of hypertension increased significantly with increasing SDB measures, although some of this association was explained by body mass index (BMI). After adjusting for demographics and anthropometric variables (including BMI, neck circumference, and waist-to-hip ratio), as well as for alcohol intake and smoking, the odds ratio for hypertension, comparing the highest category of AHI (> or = 30 per hour) with the lowest category (< 1.5 per hour), was 1.37 (95% confidence interval [CI], 1.03-1.83; P for trend = .005). The corresponding estimate comparing the highest and lowest categories of percentage of sleep time below 90% oxygen saturation (> or = 12% vs < 0.05%) was 1.46 (95% CI, 1.12-1.88; P for trend <.001). In stratified analyses, associations of hypertension with either measure of SDB were seen in both sexes, older and younger ages, all ethnic groups, and among normal-weight and overweight individuals. Weaker and nonsignificant associations were observed for the arousal index or self-reported history of habitual snoring.

CONCLUSION

Our findings from the largest cross-sectional study to date indicate that SDB is associated with systemic hypertension in middle-aged and older individuals of different sexes and ethnic backgrounds.

Serum uric acid and risk of coronary heart disease: Atherosclerosis Risk in Communities (ARIC) Study

PURPOSE

Approximately half of previous studies on serum uric acid have reported it to be an independent risk factor for coronary heart disease (CHD). We tested this hypothesis in the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

A total of 13,504 healthy middle-aged men and women were followed prospectively for up to eight years. We identified 128 fatal and nonfatal CHD events in women and 264 in men.

RESULTS

The age-, race-, and ARIC field center-adjusted relative risk of CHD for sex-specific quartiles of serum uric acid were 1.0, 1.39, 1.08, and 2.35 in women (p for trend = 0.009) and 1.0, 1.03, 0.89, and 1.21 in men (p for trend = 0.44), respectively. However, serum uric acid was correlated positively with many risk factors, and after multivariable adjustment, there was little evidence of an association of uric acid with CHD in either sex.

CONCLUSIONS

Our results are not consistent with serum uric acid being an independent risk factor for CHD.

Hypertension and antihypertensive therapy as risk factors for type 2 diabetes mellitus. Atherosclerosis Risk in Communities Study

BACKGROUND

Previous research has suggested that thiazide diuretics and beta-blockers may promote the development of type 2 diabetes mellitus. However, the results of previous studies have been inconsistent, and many studies have been limited by inadequate data on outcomes and by potential confounding.

METHODS

We conducted a prospective study of 12,550 adults 45 to 64 years old who did not have diabetes. An extensive health evaluation conducted at base line included assessment of medication use and measurement of blood pressure with a random-zero sphygmomanometer. The incidence of new cases of diabetes was assessed after three years and after six years by measurement of serum glucose concentrations while the subjects were fasting.

RESULTS

After simultaneous adjustment for age, sex, race, education, adiposity, family history with respect to diabetes, physical-activity level, other health-related behavior, and coexisting illnesses, subjects with hypertension who were taking thiazide diuretics were not at greater risk for the subsequent development of diabetes than were subjects with hypertension who were not receiving any antihypertensive therapy (relative hazard, 0.91; 95 percent confidence interval, 0.73 to 1.13). Likewise, subjects who were taking angiotensin-converting-enzyme inhibitors and calcium-channel antagonists were not at greater risk than those not taking any medication. In contrast, subjects with hypertension who were taking beta-blockers had a 28 percent higher risk of subsequent diabetes (relative hazard, 1.28; 95 percent confidence interval, 1.04 to 1.57).

CONCLUSIONS

Concern about the risk of diabetes should not discourage physicians from prescribing thiazide diuretics to nondiabetic adults who have hypertension. The use of beta-blockers appears to increase the risk of diabetes, but this adverse effect must be weighed against the proven benefits of beta-blockers in reducing the risk of cardiovascular events.

Carotid wall thickness is predictive of incident clinical stroke: the Atherosclerosis Risk in Communities (ARIC) study

Few studies have determined whether carotid artery intima-media thickness (IMT) is associated prospectively with risk of first ischemic stroke. In the Atherosclerosis Risk in Communities Study, carotid IMT, an index of generalized atherosclerosis, was defined as the mean of IMT measured by B-mode ultrasonography at six sites of the carotid arteries. The authors assessed the relation of mean IMT to stroke incidence over 6-9 years' follow-up (1987-1995) among 7,865 women and 6,349 men aged 45-64 years without prior stroke at baseline in four US communities. There were 90 incident ischemic stroke events for women and 109 for men. In sex-specific Cox proportional hazards models adjusting only for age, race, and community, the hazard rate ratios comparing extreme mean IMT values (> or =1 mm) to values less than 0.6 mm were 8.5 for women (95% confidence interval: 3.5, 20.7) and 3.6 for men (95% confidence interval: 1.5, 9.2). The relation was graded, and models with cubic splines indicated significant nonlinearity, with hazards increasing more rapidly at lower IMTs than at higher IMTs. Thus, models using linear IMT values substantially underestimate the strength of the association at lower IMTs. The strength of the association was reduced by the inclusion of putative stroke risk factors, but it remained elevated at higher IMTs. Hence, mean carotid IMT is a noninvasive predictor of future ischemic stroke incidence.

Trends in plasma cholesterol levels in the atherosclerosis risk in communities (ARIC) study

BACKGROUND

Data from the Atherosclerosis Risk in Communities (ARIC) cohort study were examined both cross-sectionally and intraindividually to confirm recent findings from population-based studies showing a decline in total cholesterol (TC) levels in the United States.

METHODS

For the cross-sectional analysis, mean plasma TC levels from 15,792 participants aged 45-64 at baseline visit, and who were selected randomly from four U.S. communities, were examined for each year covered by the first cohort visit (1987, 1988, and 1989). Ninety-three percent of the cohort participants returned for the follow-up visit (1990, 1991, and 1992), and were included in the assessment of intraindividual TC trends.

RESULTS

Both mean TC and prevalence of hypercholesterolemia (defined as plasma cholesterol concentration >/=240 mg/dl) consistently declined over the 3 years covered by visit 1 for all age-gender-race groups. For 1987, 1988, and 1989, mean TC values (mg/dl) were, respectively, 220.3, 216.7, and 214.1 (annual average change, -1.4%, P < 0.001). For these same years, hypercholesterolemia prevalence rates were 30. 0, 27.8, and 25.3% (annual average change, -7.8%, P < 0.001). The mean plasma TC also decreased within individuals between the two visits across race, gender, and age decade categories. With the exception of black men, this decline was more marked for older than younger subjects, but no consistent differences were seen between the racial groups. However, in whites, decreases were greater for men than for women. Expected results were seen when these changes were correlated with changes in cardiovascular risk factors between the two visits.

CONCLUSION

The current study results are consistent with those of previous studies, and confirm the notion that preventive programs appear to be effective in reducing mean population TC levels.

Determinants of population changes in fibrinogen and factor VII over 6 years: the Atherosclerosis Risk in Communities (ARIC) Study

Although numerous cross-sectional studies have identified possible determinants of plasma fibrinogen and factor VII levels, few prospective studies exist. We assessed the longitudinal relation of changes in fibrinogen and factor VII over 6 years with changes to other cardiovascular risk factors in a sample of 440 men and 549 women from the Atherosclerosis Risk in Communities (ARIC) study. Fibrinogen increased more in older participants, those with or who developed diabetes, those who at any time smoked, and those whose plasma HDL cholesterol or triglycerides decreased and increased less in female participants who started hormonal replacement therapy. Factor VII coagulant activity increased more in younger participants, women, those who gained greater weight or developed diabetes, those who quit smoking, those in whom plasma triglycerides decreased, and female participants who received hormonal replacement therapy. Thus, our longitudinal data suggest with some exceptions that adverse changes in cardiovascular risk factors are accompanied by increases in plasma levels of fibrinogen and factor VII.

Uric acid and serum antioxidant capacity: a reaction to atherosclerosis?

BACKGROUND

the evidence of a potential beneficial role of antioxidants in preventing atherosclerotic disease is not entirely consistent.

OBJECTIVE

to assess the longitudinal association of serum total antioxidant capacity and serum antioxidants with the presence of subclinical carotid atherosclerosis.

METHODS

Prospective case-control study nested within an historical cohort. Cases were 150 individuals with elevated carotid intimal-medial thickness measured by B-mode ultrasound at the first two examinations of the Atherosclerosis Risk in Communities Study (1987-92). Controls were 150 age-gender-matched individuals with low carotid intimal-medial thickness. Serum antioxidant vitamins, uric acid, and serum total antioxidant capacity were measured in frozen serum samples collected from the same individuals in 1974 (13-15 years prior to the determination of case-control status).

RESULTS

Compared to controls, atherosclerosis cases had significantly higher levels of serum total antioxidant capacity in 1974 than controls. This difference was almost entirely explained by increased serum concentration of uric acid in cases. In contrast with cross-sectional results, uric acid serum concentration in 1974, was significantly higher in cases than in controls, even after adjusting for the main cardiovascular risk factors. Cases had significantly lower levels of alpha-carotene in the 1974 sera than controls, but no other differences in serum antioxidant vitamin concentrations were observed.

CONCLUSIONS

The higher serum uric acid concentration seemed associated with elevated total serum antioxidant capacity among individuals with atherosclerosis. This finding is consistent with experimental evidence suggesting that hyperuricemia may be a compensatory mechanism to counteract oxidative damage related to atherosclerosis and aging in humans.

Estimating the magnitude of close-up work in school-age children: a comparison of questionnaire and diary instruments

BACKGROUND

Numerous scientists have noted a relationship between close-up work and myopia.

METHODS

A questionnaire and four 24-hour diaries were developed to estimate close-up work activity in a cohort study of close-up work and myopia progression in Singapore children. The number of hours per day that children engaged in each type of close-up work activity over a weekday and weekend during the school term, during the examination period, and in the vacation were estimated.

RESULTS

The children spent an average of 6.6 hours per day on total weighted average close-up work, of which 4.3 hours were spent on reading and writing. The intra-class correlation coefficient for the reproducibility of the questionnaire was 0.87 (95% CI 0.85-0.91). The intra-class correlation coefficient for total weighted close-up work was 0.50 (95% CI 0.34-0.66) when the questionnaire was compared with the four 24-hour diaries. The amount of close-up work activity increased with age.

CONCLUSIONS

A questionnaire for close-up work was developed and proven to be reproducible and comparable to four 24-hour diaries.

Risk factors for popliteal and carotid wall thicknesses in the Atherosclerosis Risk in Communities (ARIC) Study

The authors evaluated risk factors potentially associated with the development of popliteal artery atherosclerosis in a population-based study and compared them with factors linked to carotid wall intimal-medial thickness. The Atherosclerosis Risk in Communities (ARIC) Study is a longitudinal investigation of cardiovascular disease in 15,800 individuals. The present analyses are based on the baseline popliteal and carotid ultrasonography examination in 10,002 subjects conducted in 1987-1989. After adjustment for covariates, both carotid and popliteal intimal-medial thicknesses were strongly associated with male sex and age (p < 0.01), having a graded relation with increasing quartiles of plasma total cholesterol and low density lipoprotein cholesterol and with plasma triglycerides (women only for popliteal) (p < 0.01). An inverse correlation was noted between plasma high density lipoprotein cholesterol and carotid (p < 0.01) and popliteal (women only) (p < 0.05) intimal-medial thicknesses. Cigarette use (p < 0.01), a history of diabetes mellitus (p < 0.01), alcohol use, elevated systolic pressures (p < 0.01), and fibrinogen levels (p < 0.01) were directly associated with both popliteal and carotid intimal-medial thicknesses. Although menopause was associated with thickened carotid (p < 0.01) and popliteal (p < 0.05) intimal-medial thicknesses, hormone replacement therapy was associated with thinner carotid walls only (p < 0.05). Although there were some differences, many of the classical risk factors associated with cardiovascular disease were also related to early thickening of both the popliteal and the carotid artery walls.

Serum and dietary magnesium and the risk for type 2 diabetes mellitus: the Atherosclerosis Risk in Communities Study

BACKGROUND

Experimental studies in animals and cross-sectional studies in humans have suggested that low serum magnesium levels might lead to type 2 diabetes; however, this association has not been examined prospectively.

METHODS

We assessed the risk for type 2 diabetes associated with low serum magnesium level and low dietary magnesium intake in a cohort of nondiabetic middle-aged adults (N = 12,128) from the Atherosclerosis Risk in Communities Study during 6 years of follow-up. Fasting serum magnesium level, categorized into 6 levels, and dietary magnesium intake, categorized into quartiles, were measured at the baseline examination. Incident type 2 diabetes was defined by self-report of physician diagnosis, use of diabetic medication, fasting glucose level of at least 7.0 mmol/L (126 mg/dL), or nonfasting glucose level of at least 11.1 mmol/L (200 mg/dL).

RESULTS

Among white participants, a graded inverse relationship between serum magnesium levels and incident type 2 diabetes was observed. From the highest to the lowest serum magnesium levels, there was an approximate 2-fold increase in incidence rate (11.1, 12.2, 13.6, 12.8, 15.8, and 22.8 per 1000 person-years; P = .001). This graded association remained significant after simultaneous adjustment for potential confounders, including diuretic use. Compared with individuals with serum magnesium levels of 0.95 mmol/L (1.90 mEq/L) or greater, the adjusted relative odds of incident type 2 diabetes rose progressively across the following lower magnesium categories: 1.13 (95% CI, 0.79-1.61), 1.20 (95% CI, 0.86-1.68), 1.11 (95% CI, 0.80-1.56), 1.24 (95% CI, 0.86-1.78), and 1.76 (95% CI, 1.18-2.61) (for trend, P = .01). In contrast, little or no association was observed in black participants. No association was detected between dietary magnesium intake and the risk for incident type 2 diabetes in black or white participants.

CONCLUSIONS

Among white participants, low serum magnesium level is a strong, independent predictor of incident type 2 diabetes. That low dietary magnesium intake does not confer risk for type 2 diabetes implies that compartmentalization and renal handling of magnesium may be important in the relationship between low serum magnesium levels and the risk for type 2 diabetes.

Blood cholesterol and apolipoprotein B levels in relation to intakes of animal and plant proteins in US adults

Few studies have examined the association between specific sources of protein and blood lipids in a national sample of adults. We examined this relationship in a sample of adults 20 years and older who participated in phase 1 (1988-91) of the Third National Health and Nutrition Examination Survey, a representative sample of the United States non-institutionalized population. After excluding those participants who reported having been told they had high blood cholesterol concentrations, the final sample size was 6228. Mean intakes of different sources of proteins, as a percentage of total protein, were compared in quartiles of blood lipids. Intakes were adjusted for age, sex and race. Additional adjustments were made for other dietary variables, recall day, BMI, smoking, and income. We observed a lower percentage meat, fish and poultry (MFP) protein intake, including a lower percentage of beef and pork protein, among persons in the lowest quartile of serum total cholesterol and apolipoprotein B (ApoB) concentrations than among persons in the higher quartiles. The percentage of plant protein intake was higher in the lowest quartile than in the highest quartile of serum cholesterol. We also observed a higher percentage of fruit protein intake with lower serum cholesterol and ApoB concentrations. We conclude that in this cross-sectional sample, consumption of MFP proteins was consistently higher among persons with higher cholesterol concentrations while consumption of plant proteins was consistently higher among persons with lower cholesterol concentrations. Our findings support the importance of assessing intake of specific protein sources, especially in studies that address dietary intake in relation to blood lipids.

Prospective study of markers of hemostatic function with risk of ischemic stroke. The Atherosclerosis Risk in Communities (ARIC) Study Investigators

BACKGROUND

Several markers of hemostatic function and inflammation have been associated with increased risk of coronary heart disease, but prospective evidence for their role in ischemic stroke is scant.

METHODS AND RESULTS

The Atherosclerosis Risk in Communities (ARIC) Study measured several of these markers in more than 14 700 participants 45 to 64 years old who were free of cardiovascular disease and were followed up for 6 to 9 years for occurrence of ischemic stroke (n=191). There was no apparent association between ischemic stroke incidence and factor VIIc, antithrombin III, platelet count, or activated partial thromboplastin time. After adjustment for multiple cardiovascular risk factors, von Willebrand factor, factor VIIIc, fibrinogen, and white blood cell count were positively associated and protein C was negatively but nonsignificantly associated with ischemic stroke incidence in regression analyses based on either continuous variables or fourths of the variable distributions. The adjusted relative risk (and 95% CI) for ischemic stroke in those in the highest versus lowest fourth were: von Willebrand factor, 1.71 (1.1 to 2.7); factor VIIIc, 1.93 (1.2 to 3.1); white blood cell count, 1.50 (0.9 to 2.4); fibrinogen, 1.26 (0.8 to 2.0); and protein C, 0.65 (0.4 to 1.0).

CONCLUSIONS

This study offers modest support for the hypothesis that some markers of hemostatic function and inflammation can identify groups of middle-aged adults at increased risk of stroke. These factors may play a role in the pathogenesis of ischemic stroke.

Retinal arteriolar diameters and elevated blood pressure: the Atherosclerosis Risk in Communities Study

Narrowing and other changes in retinal arterioles may reflect damage due to hypertension, which may predict stroke and other cardiovascular diseases independently of blood pressure level. Newly developed quantitative methods of assessing retinal narrowing are used to determine whether this sign is related only to current blood pressure or whether it also independently reflects the effects of previous blood pressure. Retinal photography was performed at the third examination of Atherosclerosis Risk in Communities (ARIC) Study in 1993-1995, and results are presented for the 9,300 nondiabetic participants aged 50-71 years. Generalized narrowing of smaller arterioles was strongly and monotonically related to current blood pressure in men and women, whether they were taking antihypertensive medications or not, and, independent of current blood pressure, was consistently and monotonically related to blood pressure levels measured 3 and 6 years before the retinal assessment. Arteriovenous nicking was also independently related to both current and previous blood pressures. The patterns of association suggested that these signs reflect both transient and persisting structural effects of elevated blood pressure, in agreement with the scant pathologic literature available. The findings suggest that retinal assessment may be useful for research on the microvascular contributions to clinical cardiovascular diseases.

Chlamydia pneumoniae infection and incident coronary heart disease: the Atherosclerosis Risk in Communities Study

Pathologic findings and cross-sectional epidemiologic studies suggest that past infection with Chlamydia pneumoniae is associated with clinical and subclinical atherosclerotic disease, although evidence from prospective studies is still scarce. The association between chronic infection by C. pneumoniae and incident coronary heart disease (CHD) was investigated in a case-cohort study conducted among participants in the Atherosclerosis Risk in Communities Study who were free of CHD at the baseline examination (1986-1989). Levels of C. pneumoniae immunoglobulin G (IgG) antibodies in serum collected at baseline from 246 incident cases of CHD identified during follow-up (median, 3.3 years; maximum, 5 years) were compared with those from a stratified sample of the baseline cohort (n = 550). Among incident CHD cases, 65% had IgG antibody titers > or =1:64, compared with 55% of noncases (compared with negative IgG titers, the relative hazard of CHD was 1.6 (p < 0.01)). In multivariate analyses controlling for other risk factors (age, gender, smoking, serum cholesterol, hypertension, diabetes mellitus, and educational level), the above estimates were substantially reduced and became statistically nonsignificant (relative hazard = 1.2). A significantly increased CHD hazard associated with IgG antibody titers > or =1:64 was observed among nonsmokers, even after adjustment for other risk factors. Overall, these results do not provide strong support for the hypothesis that C. pneumoniae infection is a risk factor for clinical CHD. Studies with longer follow-up periods will be necessary to determine whether C. pneumoniae infection is involved as an etiologic factor in earlier phases of atherogenesis.

Estimates of animal and plant protein intake in US adults: results from the Third National Health and Nutrition Examination Survey, 1988-1991

OBJECTIVE

To describe the sources of protein intake in a sample of the US adult population and among subgroups defined by race-ethnicity, age, and gender.

DESIGN

The Third National Health and Nutrition Examination Survey, 1988-1991, is a stratified random sample of the total civilian noninstitutionalized population, drawn from the 50 United States and the District of Columbia. For all foods consumed by the participants, based on a 24-hour dietary recall, protein sources and the contribution of each protein type to the total protein intake were determined.

SUBJECTS

Adult participants in the third National Health and Nutrition Examination Survey (n = 7,924).

STATISTICAL ANALYSES

Weighted total, age-specific, and age-adjusted mean protein intakes were calculated using SAS and WesVarPC. Statistical differences were determined by 2-tailed t tests.

RESULTS

The main protein source in the American diet is animal protein (69%). Meat, fish, and poultry protein combined contributed the most to animal protein (42%), followed by dairy protein (20%). Grains (18%) contributed the most to plant protein consumption. Women consumed a lower percentage of beef (14%) and pork (7%) protein than did men (18% and 9%, respectively). Women also consumed a higher percentage of poultry (13%), dairy (22%), and fruit and vegetable (11%) protein than did men (11%, 19%, and 9%, respectively). Blacks reported eating a higher percentage of poultry (18%) and pork (11%) protein and a lower percent of dairy protein (14%) than did whites (12%, 7%, and 22%, respectively) and Mexican-Americans (11%, 8%, and 17%, respectively). Mexican-Americans consumed a higher percentage of legume (7%) and egg (7%) protein than did whites (4% and 4%, respectively) and blacks (4% and 5%, respectively). Whites consumed a higher percentage of grain protein (19%) than did blacks (16%) and Mexican-Americans (15%).

CONCLUSIONS

These results show that, although the percentage of total energy from protein may be similar among race-ethnicities and between men and women, their sources of protein are different. These differences should be taken into account when providing nutrition education for specific populations.