Biomedical subjects
Publications and source records attributed to M H Criqui.
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The association between alcohol intake and atherosclerotic cardiovascular disease (CVD) in epidemiological studies is consistent and shows some protection from CVD at consumption levels of one to two drinks per day, but a sharp increase in CVD associated with three or more drinks per day. Analyses of potential mediators of effects of alcohol on CVD show that it increases high density lipoprotein (HDL) cholesterol levels and favourably influences thrombotic factors, especially fibrinogen, and also fibrinolytic factors. Some evidence also suggests moderate alcohol consumption may reduce insulin resistance. However, studies also show an adverse effect of alcohol, particularly at higher doses, on blood pressure (leading to hypertension) and directly on the myocardium (leading to arrhythmias and myocardiopathy). Statistical modelling of the alcohol-CVD relationship is consistent in several studies, with a protective pathway via elevated HDL cholesterol and an adverse pathway through elevated blood pressure. Other possible mediators influenced by alcohol have not yet been examined in this type of analysis. The French Paradox has led to speculation that wine is the only protective alcoholic beverage for CVD, or at least that it has a stronger effect. Multiple non-ethanol components of wine have been studied in the laboratory and have been shown to have antioxidant or anticoagulant effects. Although wine does appear more protective in ecological studies, studies within cohorts show similar effects across alcoholic beverages, suggesting confounding in ecological studies by diet, lifestyle, or other variables. The key component of alcoholic beverages thus appears to be ethanol, consistent with the known potent effects of ethanol on HDL cholesterol and thrombotic factors. The upswing in CVD risk with three or more drinks per day is sharp and emphasizes that benefit from alcohol is limited to moderate consumption only. This upswing also cautions against any public health recommendation to drink alcohol, since many persons will not or cannot limit their intake to moderate levels.
OBJECTIVES: The Walking Impairment Questionnaire (WIQ) was designed to measure community walking ability in patients with peripheral arterial disease (PAD) and intermittent claudication. We compared the WIQ scores to objective measures of walking in a heterogeneous group of patients with and without PAD. METHODS: The study was designed as a cross-sectional study, with the setting in an academic medical center. The subjects were patients with PAD (n = 145) who were identified from a noninvasive vascular laboratory at an academic medical center. The patients without PAD (n = 65) were identified from a general medicine practice. The average number of comorbidities was 2.03 for patients with PAD and 1.52 for patients without PAD. Among the patients with PAD, 28% had classical intermittent claudication symptoms and 55% had exertional leg symptoms other than claudication. The main outcome measures were the WIQ estimates of the patient-reported walking distance and walking speed on a scale of 0 to 100. Walking endurance was measured objectively with the 6-minute walk. Walking velocity was measured with a 4-m walk. PAD and PAD severity were defined with the ankle brachial index. RESULTS: The Spearman rank correlation coefficients (rho) between the WIQ distance score and the 6-minute walk score were 0.557 among patients with PAD (P <.001) and 0.484 among patients without PAD (P <.001). The correlation coefficients between the WIQ speed score and the usual-paced 4-m walk score were 0.528 among patients with PAD (P <.001) and 0.524 among patients without PAD (P <.001). The correlations were not affected by the presence versus the absence of intermittent claudication, by PAD severity, or by the presence of 2 or more versus less than 2 comorbid illnesses. The WIQ scores in the highest and lowest quartiles were the most closely associated with the objective measures of function. CONCLUSION: The WIQ is a valid measure of community walking ability in a heterogeneous group of patients with and without PAD. The WIQ discriminates best among patients in the highest and the lowest quartiles of walking speed and endurance.
Low literacy skills may negatively affect health through misuse of medication, inability to follow medical directions or due to limitations placed on the consumer's ability to access health information. The association between low literacy among adults and cardiovascular disease has not been thoroughly investigated in some ethnic groups. The purpose of this comprehensive study is to describe the results of a nutritional-related cardiovascular health program for limited English proficient adults enrolled in English-as-a-second-language (ESL) classes. Subjects (n = 408), nearly 87% of whom were Latino, were exposed to either nutrition education (intervention group) or stress management (attention-placebo control group) classes designed specifically for ESL classes. Subjects completed physiological measures assessing blood pressure, total and high-density lipoprotein (HDL) cholesterol, waist and hip circumference, and body mass. Self-report surveys were administered to collect students' nutrition-related knowledge, attitudes and behaviors. Data were collected at baseline, 3 month post-test and 6 month follow-up. Analyses showed that differential group change was seen for fat avoidance, nutrition knowledge, HDL and total cholesterol:HDL ratio, but, for the two latter variables, the effect was not maintained at the 6 month follow-up. Both groups showed positive changes in blood pressure, total cholesterol and nutrition-related attitudes. Results showed moderate success of the intervention, but suggest contamination between experimental groups may have occurred.
OBJECTIVES: Maintaining function among older men and women is an important public health goal as the population lives longer with chronic disease. We report the relationships between lower extremity peripheral arterial disease (PAD), PAD severity, and PAD-related symptoms with walking velocity and endurance among men and women aged 55 and older. DESIGN: A cross-sectional design. SETTING: An academic medical center. PARTICIPANTS: Participants with PAD were men and women aged 55 and older identified from a blood flow laboratory or a general medicine practice (n = 158). Randomly selected controls without PAD were identified from the general medicine practice (n = 70). MEASUREMENTS: PAD was diagnosed and quantified using the ankle brachial index (ABI). Subjects were categorized according to whether they had severe PAD (ABI <0.40), mild to moderate PAD (ABI 0.40 to <0.90), or no PAD (ABI 0.90 to <1.50). Walking endurance was assessed with the 6-minute walk. Usual walking velocity and maximal walking velocity were assessed with "usual" and "maximal" paced 4-meter walks, respectively. RESULTS: Average distances achieved in the 6-minute walk were 1569+/-390 feet for subjects with ABI 0.90-1.50, 1192+/-368 feet for subjects with ABI 0.40 to <0.90, and 942+/-334 feet for subjects with ABI < 0.40 (trend P value < .001). Walking velocities for both the usual and maximal paced 4-meter walks were slowest among subjects with ABI < 0.40 and fastest among subjects with ABI 0.90 to <1.50. Subjects with PAD who had pain at rest had slower walking velocity and poorer walking endurance than other subjects with PAD. In multiple linear regression analyses that included subjects with PAD only, ABI level was an independent predictor of 6-minute walk performance (regression coefficient = 159 ft/0.40 ABI units, P = .011), usual paced 4-meter walk (regression coefficient = .095 meters/sec/0.40 ABI units, P = .031), and maximal paced 4-meter walk (regression coefficient = .120 meters/sec/0.40 ABI units, P = .050) adjusting for age, sex, race, leg symptoms, and comorbid diseases known to affect functioning. Pain at rest was associated independently with the maximally paced 4-meter walk (-0.201 meters/sec, P = .024), but not with the other walks. CONCLUSION: ABI level has a measurable and independent association with walking endurance and both usual and maximal walking velocity. These data suggest that PAD may impair lower extremity function by diminishing function of both Type I ("slow twitch") and Type II ("fast twitch") muscle fibers. Because walking velocity has important prognostic implications for functioning, these data also suggest that ABI may be used to identify patients at increased risk of mobility loss.
Non-invasive measurements, especially segmental pressure ratios and flow measurements, are useful for gauging the severity of peripheral arterial disease (PAD). Although the incidence of PAD is similar for men and women, men are more likely to have severe disease, while women usually have more moderate or asymptomatic disease. Published reports confirm the clinical impression that patients with PAD are more likely to have both coronary artery disease and cerebrovascular disease than those without PAD. However, the degree of overlap is a function of the sensitivity of the diagnostic assessments for the three conditions. A San Diego population study found that the incidence of PAD may be underestimated, with many patients being asymptomatic. Based on blood flow measurements, the study found that 11.9% of the study population had large vessel PAD. Morbidity from both coronary heart disease and stroke was increased in people with PAD, who were 2.5 times more likely to present with morbidity from cardiovascular disease (CVD) than those who did not have PAD. Several studies have now confirmed the strong predictive value of PAD for subsequent CVD mortality and that the risk of CVD mortality increases with the severity of PAD.
Observational studies, both case control and prospective, have routinely identified elevated triglycerides as a univariate predictor of cardiovascular disease, especially coronary heart disease, and in several studies this association persists in multivariate analysis. However, experimental information from clinical trials is required for clinical guidelines. Many clinical trials in dyslipidaemia have employed interventions with only minor effects on triglycerides. Five trials have used pharmaceutical agents with significant triglyceride effects and have correlated the clinical or angiographic benefit observed with the change in various lipid or lipoprotein components. In three of these five trials, the benefit for various coronary disease endpoints was more closely associated with triglyceride reductions than with changes in other lipids and lipoproteins. A sixth trial showed reduced coronary disease progression with treatment despite no change in LDL cholesterol. Reduction in triglycerides may result in direct benefit for coronary disease. Clinical trials employing pharmacological agents with significant effects on triglycerides should correlate clinical and/or angiographic benefit with observed lipid and lipoprotein changes, as well as any changes in non-lipid risk factors such as fibrinogen.
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At present a large number of patients with atherosclerotic disease are not receiving aggressive cholesterol-lowering therapy. Consequently they are being deprived of a cost-effective, risk-reducing treatment. Every physician who treats patients with clinical atherosclerotic disease should become fully informed about the results of cholesterol-lowering trials in patients at high risk. All physicians who care for high-risk patients should take responsibility for cholesterol management, including primary care physicians and cardiovascular specialists. Highly effective and generally safe drugs for cholesterol lowering are available. The benefits of therapy for reducing recurrent CHD and prolonging life are considerable. There is no justification for unduly delaying institution of therapy for the majority of patients. The many advantages of nonpharmaceutical therapy call for its use in almost all patients, but drug treatment should not be postponed if the target for LDL cholesterol lowering (< or = 100 mg/dL) is unlikely to be achieved in the near term by a nonpharmaceutical approach alone. The view that patients with CHD or other forms of atherosclerotic disease do not receive substantial clinical benefits from aggressive cholesterol-lowering therapy is no longer warranted. Intensive cholesterol reduction, initiated immediately, has the potential to significantly reduce both morbidity and mortality. Cholesterol-lowering therapy thus should become a routine part of clinical management to reduce risk of future coronary events and to prolong life in patients with CHD or other forms of atherosclerotic disease.
Using an archival prospective design, the authors studied associations among parental divorce occurring during participants' childhood, adult psychosocial mediators, and mortality over the life span of a subgroup of participants (N = 1,261) in the Terman Life Cycle Study (1921-1991). Children from divorced families grew up to show a higher risk of premature mortality across the life span. The higher mortality risk for men was explained, in part, when 3 mediating factors were controlled: Men who had experienced parental divorce were more likely to have their own marriages end in divorce, obtained less education, and engaged in fewer service activities. Women who had experienced parental divorce smoked more and were more likely themselves to divorce, both of which predicted higher mortality risk. The findings extend previous work on the negative sequelae of parental divorce to long-term effects on personality and longevity.
Data from the Framingham Study and other population studies indicate that intermittent claudication (IC) sharply increases in late middle age and is somewhat higher among men than women. Noninvasive testing in populations indicates that the true prevalence of peripheral arterial disease (PAD) is at least five times higher than would be expected based on the reported prevalence of IC. Peripheral arterial disease correlates most strongly with cigarette smoking and either diabetes or impaired glucose tolerance. Other risk factors for PAD include hypertension; low levels of high-density lipoprotein cholesterol; and high levels of triglycerides, apolipoprotein B, lipoprotein(a), homocysteine, fibrinogen and blood viscosity. Individuals with PAD are more likely to have coronary heart disease and cerebrovascular disease than those without PAD. Because of the high risk of both nonfatal and fatal cardiovascular disease (CVD) events in PAD patients, individuals with evidence of PAD should undergo both a careful examination of the entire cardiovascular system and aggressive modification of CVD risk factors.
BACKGROUND: The Preventive Cardiology Center compared two intensities of behavior modification for cardiovascular disease (CVD) risk factors in persons at risk and their families. Characteristics of drop-outs both before and after intervention were compared with subjects who completed the 6-month trial. METHODS: A total of 333 individuals of all ages were enrolled in the study and randomly assigned by family to a single-session ('skills' group-low-intensity) or a five-session ('practice' group-high intensity) intervention. Baseline and follow-up assessments included a personal and family health questionnaire, nutritional intake survey, and clinic visit to obtain blood pressure, lipids, and height and weight data. RESULTS: Two hundred and forty adults over 18 years of age were randomly assigned to one of the two intervention groups. Of these, 68 subjects (28.3%) did not participate in the intervention. Multivariate analysis revealed that these 'early drop-outs' were significantly more likely to be non-white and to have had a lower LDL cholesterol. Of the 172 subjects attending the intervention, 70 (40.7%) did not attend the 6-month follow-up ('late drop-outs'). Multivariate analysis revealed that, compared with follow-up attendees, non-attendees were significantly more likely to be white and to be current smokers. CONCLUSIONS: Both early and late drop-outs in a randomized trial of CVD risk reduction were significantly different than continuing participants in several key factors. These differences suggest the use of caution in both interpreting and making generalizations about behavioral trials of risk factor reduction when attrition is high.
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The relationship between alcohol consumption and coronary heart disease (CHD) in various epidemiologic study designs is consistent, showing protection at < or = 2 drinks per day, with an increase in risk of CHD in several studies at higher alcohol consumption levels. Studies of potential mediators of the effects of alcohol on CHD show beneficial effects on HDL cholesterol and some coagulation factors, but, at higher levels of consumption, adverse effects on blood pressure, arrhythmias, and the myocardium. Statistical modeling of pathways for alcohol's effect on coronary disease is consistent with a protective pathway via elevated HDL cholesterol and an adverse pathway through elevated blood pressure. Maximum benefit for CHD appears to be reached at only one drink daily. Given that alcohol is an intoxicating and potentially addictive substance with a high abuse potential, and given the high morbidity and mortality associated with heavier drinking, public health recommendations to consume alcohol are contraindicated.
Established risk factors cannot explain all the variance in coronary heart disease (CHD). Immunoglobin E (IgE), a mediator of allergy, can affect platelets and arterial smooth muscle. We previously demonstrated a cross-sectional association between IgE and cardiovascular disease (CVD) in men. The present study evaluated this relationship prospectively in 278 men and 343 women followed for a mean of 8.9 years. There was an association between IgE and coronary disease in men, but not in women. There was no association for CVD, stroke, or all-cause mortality. The age-adjusted relative risk (RR) for coronary mortality in men with baseline IgE > or = 200 kU/L was 1.66 (p < or = 0.66), but for nonfatal myocardial infarction (MI) it was 6.46 (p < or = 0.01). This association was independent of smoking and other risk factors, and unrelated to allergy. Thus, elevated IgE was a strong independent prospective risk factor for nonfatal, but not fatal, MI in men.
The objective of this study was to determine whether birth order is associated with total or cause-specific adult mortality and whether the association differed by sex, was confounded by age, number of siblings, or socioeconomic status, or was mediated by personality, education, or health behaviors. Teachers throughout California identified intellectually gifted children as part of a prospective study begun in the 1920s by Lewis Terman. Information on birth order was available on 1162 subjects (85% of cohort) who have since been followed for over 70 years. Cox proportional hazards models indicated that birth order was not associated with adult all-cause, cardiovascular, or cancer mortality. Among women, middle children were more likely than oldest children to die from causes of death other than cardiovascular disease or cancer, although the numbers in this category were small. This study did not provide evidence that birth order is associated with adult mortality in this highly intelligent, middle-class cohort.
The WHO/Rose questionnaire has served as the epidemiologic and clinical standard in the assessment of leg pain in patients with peripheral arterial disease (PAD) for over three decades. However, the structure of this questionnaire does not allow assessment of leg-specific (i.e. right versus left) symptoms. We studied 508 patients aged 39-95 years (mean 68 years), initially referred for PAD non-invasive testing. A revised questionnaire, the San Diego Claudication Questionnaire, was administered which allowed determination of leg-specific symptoms and evaluated thigh and buttock as well as calf pain. Leg-specific symptoms were categorized into no pain, pain at rest, non-calf claudication, non-Rose calf claudication, and Rose claudication. At the same visit, the ankle brachial index, the toe brachial index, and peak posterior tibial flow velocity were measured by Doppler ultrasound and five categories of non-invasive results by type and severity of PAD were defined. Legs with previous intervention (Rx), surgery or angioplasty, were evaluated separately. Claudication was reported in 42% of no Rx legs and 50% of Rx legs; 40% of claudication was atypical (not Rose); 64% of no Rx and 81% of Rx legs had PAD by non-invasive testing, and 27% of affected legs had severe PAD. The correlation between the severity of symptoms and the severity of ipsilateral PAD in no Rx legs was r = -0.40, p < 0.001. In Rx legs, this correlation was somewhat less (r = 0.27, p < 0.001) due to more symptomatology at lesser degrees of PAD, suggesting reporting bias and/or more residual disease than evident from non-invasive testing. To our knowledge, these results provide the first comparison between a standardized assessment of leg pain and the severity of ipsilateral PAD by non-invasive testing.