Biomedical subjects

C A Derby

Publications and source records attributed to C A Derby.

31 records · Page 2Linked to original sources

PubMed1995

Cardiovascular risk profiles of oral contraceptive users and nonusers: a population-based study.

BACKGROUND: The purpose of this population-based study was to evaluate whether women taking oral contraceptive products (OCPs) have more favorable cardiovascular disease (CVD) risk profiles than women not taking OCPs. METHODS: Data including sociodemographic variables and CVD risk factors from 5,239 women of reproductive age were gathered in six cross-sectional household surveys. Differences in CVD risk factor profiles between OCP users and nonusers were compared using logistic regression. younger users and older users were compared with nonusers of the same age groups. RESULTS: Women using OCPs (n = 807) were younger and had higher socioeconomic status than nonusers (n = 4,432). More users than nonusers were current smokers (43.1% vs 36.6%, P = 0.0011), had a total serum cholesterol level > or = 240 mg/dl (12.7% vs 6.0%, P = 0.0001), and tended to rate themselves to be at low risk for CVD (48.3% vs 45.5%, P = 0.17). Fewer OCP users than nonusers had an HDL cholesterol level < or = 35 mg/dl (4.0% vs 6.9%, P = 0.0039). CONCLUSIONS: Although they tended to perceive themselves to be at low risk, women taking OCPs in this study had worse CVD risk profiles than women not reporting hormonal contraception and are candidates for cardiovascular risk reduction strategies.

Adolescent↗

PubMed1995

Prior and current health characteristics of postmenopausal estrogen replacement therapy users compared with nonusers.

OBJECTIVE: Our purpose was to investigate whether selection of healthy women for postmenopausal estrogen therapy may confound observational studies of estrogen use and cardiovascular disease risk. STUDY DESIGN: Data were obtained from baseline (1981 to 1984) and follow-up (1990 to 1992) health surveys of two cohorts randomly selected from communities in southeastern New England. At follow-up postmenopausal women > or = 40 years old were categorized as current users (n = 70) or nonusers (n = 772) of noncontraceptive estrogen. Users and nonusers were compared on both prior characteristics from the baseline surveys and current characteristics measured at follow-up by use of analysis of covariance. RESULTS: Prior levels of total and high-density lipoprotein cholesterol, body mass index, and blood pressure were similar for estrogen users and nonusers. Estrogen users were less likely to have smoked and more likely to have had their cholesterol checked and to exercise regularly. These differences were more pronounced for current characteristics than for baseline characteristics. CONCLUSIONS: Selection of healthy women for treatment may not fully explain the apparent protective effect of estrogen replacement on cardiovascular risk. However, more healthy profiles among estrogen users may inflate the apparent benefit of treatment in observational studies.

Adult↗

PubMed1994

Dietary differences in smokers and nonsmokers from two southeastern New England communities.

OBJECTIVE: Previous studies based on 24-hour dietary recall data have shown that smokers tend to consume less healthful diets than nonsmokers. We tested this hypothesis using data from food frequency questionnaires (FFQs) in a group of men and women. DESIGN: Characteristics of smokers and nonsmokers were compared using data collected from a cross-sectional household health survey. SUBJECTS: Adults aged 18 through 64 years from two communities in southeastern New England were randomly selected for the study and interviewed in their homes by trained personnel. The interview included questions on demographic and behavioral characteristics. Height, weight, blood pressure, and serum lipids were measured using standard protocols. The Willett FFQ was completed by 1,608 of 2,531 eligible respondents who made up our study sample. STATISTICAL ANALYSES PERFORMED: Respondents were categorized as current cigarette smokers or nonsmokers. Demographic, behavioral, physiologic, and dietary characteristics were compared between smokers and nonsmokers by analysis of covariance with age as the covariate. RESULTS: Eligible respondents who did not complete the FFQ differed from respondents with respect to age, gender, smoking prevalence, and several other demographic characteristics. Smokers consumed more energy, fat, alcohol, and caffeine than nonsmokers. Smoking status was inversely associated with intake of vitamins A and C, dietary fiber, folate, and iron among women, whereas differences were smaller and not significant among men. Women who smoked consumed fewer servings of fruits and vegetables than nonsmokers, but this trend was not noted in men. The association between diet and smoking was only slightly diminished by multivariate adjustment for age, income, regular exercise, marital status, and working status but most clinically relevant associations remained. The interaction between gender and smoking was not statistically significant for most dietary variables. CONCLUSIONS: These results suggest that health promotion messages targeted to smokers should include dietary instructions, especially for women.

Adult↗

PubMed1994

Gender differences in the balance of healthy elderly as demonstrated by dynamic posturography.

BACKGROUND: Prior studies indicate that older women fall more often than men although there is no evidence of gender-based balance differences. Using a force platform, we measured the effects of restricted sensory input and support surface movement to detect gender differences in balance. METHODS: Healthy, elderly community dwellers (N = 234, mean age = 76 +/- 5 years, 52% female) were administered the following perturbations on the balance platform: The platform and/or visual surround were fixed or tilted proportionally to the subject's sway with the eyes open or closed, forward or backward horizontal translations, and toes-up and toes-down rotations. RESULTS: Gender-based balance differences were not present during quiet standing, or when the support surface or visual input were manipulated separately. Women swayed and lost their balance more than men when the surface was sway-referenced while vision was compromised, but by the third trial their sway control was comparable to the men. Women also initially lost their balance more frequently than men during toes-up and -down rotations, and compared to men continued to lose their balance more often during repeated toes-up rotations. Finally, women developed less angular momentum than men in response to forward platform rotations. DISCUSSION: Elderly women show impairments of balance when simultaneously deprived of visual and somatosensory inputs or during a backwards destabilization. Since there is little evidence for a CNS source for such gender differences, biomechanical origins (e.g., dorsiflexion strength and range of motion) are a more likely cause. Limited postural control of women under conditions stressing balance may explain their greater frequency of falling.

Adaptation, Physiological↗

PubMed1994

Age-associated changes in diastolic filling: Doppler E/A ratio is not associated with congestive heart failure in the elderly.

Although left ventricular filling tends to occur in late diastole in the elderly, the clinical significance of this change is unclear. To determine the prevalence of diastolic filling delay and its relationship to congestive heart failure (CHF) in the elderly, we studied 114 community-living elderly volunteers (median age 75, 37% male). Clinical history, physical examination, chest x-ray film, and Doppler echocardiogram were obtained in blinded fashion. CHF was diagnosed by a previously validated clinico-radiographic scoring system. Diastolic filling was assessed by the Doppler ratio of early to late transmitral flow velocity (E/A). The standard clinical definition of diastolic filling delay (E/A < 1) was met by 94 subjects (82%), and median E/A was 0.72; for this study, diastolic filling delay was defined at the median, although both approaches yielded similar results. Systolic function was normal (ejection fraction > or = 0.5) in 97%. There were 22 subjects (19%) with definite or possible CHF. Older subjects were more likely to have CHF, but not more likely to have an E/A ratio below the median. Subjects with diastolic filling delay were no more likely to have CHF than those without. Mean E/A was not different between CHF groups, and there was no significant correlation between E/A and CHF score. There was still no association after controlling for age, history of hypertension, and other potential confounders by multiple logistic regression. Although diastolic filling delay is common in the elderly, it does not correlate with signs and symptoms of CHF. Determination of its prognostic significance requires a prospective follow-up study.

Age Factors↗

PubMed1993

Correlates of postmenopausal estrogen use and trends through the 1980s in two southeastern New England communities.

Correlates and prevalence of current postmenopausal estrogen use were examined in two southeastern New England communities for the period 1981 through 1990. Data were obtained from five biennial cross-sectional household health surveys, with current use of postmenopausal estrogen determined by inspection of medication bottles. Analysis included 3,279 women aged 40-64 years, of whom 2,215 (67.6%) were postmenopausal. The prevalence of estrogen use among all postmenopausal women increased from 5.3% (95% confidence interval (CI) 3.2-7.4) in 1981-1982 to 10.9% (95% CI 7.5-14.4) in 1989-1990. Among women with surgical menopause, prevalence increased from 11.4% (95% CI 6.6-16.2) to 20.3% (95% CI 13.6-27.0), while use among women with natural menopause increased from 1.5% (95% CI 0.04-2.9) to 3.5% (95% CI 0.74-6.2). Logistic regression was used to compute age-adjusted prevalence of estrogen use according to demographic characteristics and cardiovascular risk factors. Postmenopausal estrogen use was positively associated with income, and a positive trend with education was suggested. Estrogen use was positively associated with high density lipoprotein cholesterol and was inversely associated with body mass index. Nonsmokers, women who exercised at least once per week, and women who reported having their cholesterol checked in the past year were more likely to use estrogen. These findings suggest that estrogen users have a more healthy profile than do nonusers. In addition, the prevalence of postmenopausal estrogen use appears to be substantially lower in women with natural versus surgical menopause throughout the period studied.

Adult↗

PubMed1992

Comparison of the plasma levels of apolipoproteins B and A-1, and other risk factors in men and women with premature coronary artery disease.

The predictors of premature coronary atherosclerosis were examined in 203 patients (99 men aged less than or equal to 50 years, and 104 women aged less than or equal to 60 years) undergoing elective diagnostic coronary arteriography. Age, cigarette smoking, hypertension, obesity, diabetes, positive family history of premature coronary artery disease (CAD), and plasma levels of total cholesterol, triglyceride, lipoproteins (i.e., very low, intermediate-, low-, and high-density [HDL] lipoproteins and their subfractions [HDL2 and HDL3], and lipoprotein [a]) and apolipoproteins (apoA-1, apoA-2 and apoB, respectively) were examined using univariate analyses and multivariate logistic regression. In men, age (p less than 0.05), smoking (p less than 0.05), and plasma triglyceride (p less than 0.02) and apoA-1 (p less than 0.05) levels were independently associated with CAD. In women, smoking (p less than 0.001) and plasma apoB levels (p less than 0.04) were the strongest variables independently associated with CAD. It is concluded that the "nontraditional" risk factors (plasma apoA-1 and apoB levels) are better predictors of premature CAD than are plasma lipoproteins and that smoking is the strongest of the traditional nonlipid risk factors.

Adult↗

PubMed1992

A dynamic posturography study of balance in healthy elderly.

Using dynamic posturography, we studied the balance of 234 community-dwelling elderly subjects (mean age, 76 +/- 5 years) as well as 34 young controls (mean age, 34 +/- 12 years). Almost all measures of balance were worse in elderly subjects compared with young controls. The decrements in older persons indicate a diminished capacity to process conflicting sensory input as well as a possible narrowing of the limit of stability (or, alternatively, an increase in sway). We propose that this occurs most likely as a result of biomechanical or central processing changes as opposed to diminished sensory or vestibular input. Furthermore, with difficult tasks sequentially presented, the performance of the older subjects improved, suggesting that balance, at least in the short term, adapts to stressful conditions. In these elderly subjects screened for age-related diseases affecting balance, only small decrements of balance occurred between the ages of 70 and 85 years. This nominal decrease over a 15-year span suggests that clinically significant balance impairment is the result of age-related disease rather than an inevitable consequence of aging and is therefore potentially treatable.

Adult↗

PubMed1992

Biological variability of lipoproteins and apolipoproteins in patients referred to a lipid clinic.

We determined the physiological variability of total cholesterol, high- (HDL) and low-density lipoprotein (LDL) cholesterol, triglycerides, and apolipoproteins A-I and B in fasting blood samples from patients referred to the Johns Hopkins Lipid Referral Clinic. Samples were taken on each of three occasions during baseline evaluation visits before the patients were treated. The median physiological coefficients of variation (CVp) were as follows: total cholesterol, 5.0%; triglycerides, 17.8%; HDL cholesterol, 7.1%; LDL cholesterol, calculated from the previous three measurements, 7.8%; and apolipoproteins A-I and B, 7.1% and 6.4%, respectively. There were no significant differences in CVp between children (less than or equal to 18 years) and adults (greater than 18 years) for any of the measurements. On the basis of our findings, single measurements in serial samples taken on three occasions suffice to establish the patients' usual values with the following precisions (+/- 1 CV): total cholesterol, +/- 4%; triglycerides, +/- 11%; HDL cholesterol, +/- 8%; LDL cholesterol, +/- 6%; and apolipoproteins A-I and B, +/- 7%.

Adolescent↗

PubMed1991

Invited commentary: should arteriographic case-control studies be used to identify causes of atherosclerotic coronary artery disease?

Arteriographic case-control studies still have a role in defining associations and dose-response relations between newly purported risk factors and atherosclerotic coronary artery disease. They remain one of the better ways to sort out whether a risk factor acts to cause clinical coronary disease via effects on coronary atherosclerosis, infarction independent of atherosclerosis, or both. It remains unclear if the selection processes for coronary arteriography infuse bias into the selection of cases, though the report by Reed and Yano suggests it does not. Control group selection remains problematic, as it does for all case-control studies, and considerable effort should be exercised to avoid the many potential biases in selection of both cases and controls. In this latter statement there is agreement with authors Reed and Yano. However, the avoidance of arteriographic studies threatens to curb the initiation of that sequence of studies that can, in a relatively short duration of time, provide useful information on the potential for a risk factor intervention to inhibit coronary atherosclerosis and, possibly, clinical coronary events. This, then, raises the final point for emphasis. Arteriographic studies, be they case-control, prospective, or experimental, may be most powerful when paired with those using clinical endpoints. In addition to the chance for replication of findings with another set of endpoints, the issue of mechanism of action via the atherosclerotic process can be addressed. Interestingly, the Honolulu Heart Program, with its laudable efforts to collect both autopsy and arteriographic quantitations of atherosclerosis, provides perhaps the best illustration in the current literature of the power of using multiple endpoints for coronary artery disease to more completely elucidate the role of risk factors in the natural history of that disease.

Angiography↗

PubMedDate not supplied

Medical students' improved attitudes toward prevention of cardiovascular diseases from entry to graduation. Preventive Cardiology Academic Cooperative Research Group of the National Heart, Lung, and Blood Institute.

First-year medical students have been previously reported to have positive attitudes about disease prevention, in general, and about cardiovascular disease prevention, in particular. Whether medical school experiences exert a positive, negative, or neutral effect on prevention-oriented attitudes in medical students is not known. We assessed attitudes toward heart disease prevention in 770 entering medical students enrolled at six selected American medical schools, each having some curricular emphasis on preventive cardiology, and repeated the attitude survey near graduation in the 750 fourth-year students enrolled in the six schools. Response rates were similar at each of the schools for each administration and averaged 88% in entering students and 74% in the graduating students. We used two mean attitude scores, ranging from 1.0 to 5.0 on a Likert scale, 5.0 representing the most positive attitude. The score treating the importance of primary prevention increased from 4.08 +/- 0.39 to 4.35 +/- 0.41. The attitude score concerning the importance of research in preventive cardiology also increased from 3.65 +/- 0.56 to 3.90 +/- 0.64 (P less than .0001 for both comparisons of first-year to fourth-year students). Analyses by school revealed similar increases, as did analyses for men, women, whites, and nonwhites. The results indicate that positive attitudes toward heart disease prevention can become even more positive during medical school. The perpetuation of positive attitudes should contribute to improved clinical prevention behaviors when these graduates embark on careers in medicine.

Adult↗

PubMedDate not supplied

Predictors of future antihypertensive use in patients with mildly elevated blood pressure.

We prospectively identified predictors of future antihypertensive use in untreated persons age 18-65 years who had elevated diastolic blood pressures of 90-104 mm Hg or systolic blood pressures of at least 140 mm Hg. Data were derived from two independent cohorts completing household surveys conducted in 1981-1984 and 8 years later, as part of the Pawtucket Heart Health Program. Demographics, self-reported health behaviors and beliefs, and physiologic measurements were obtained. Drug use was determined through structured interviews. Analysis of covariance and logistic regression were performed. In the 492 subjects, independent baseline predictors of future antihypertensive use (p < 0.05) included female gender, older age, diastolic blood pressure elevation, self-perceived high blood pressure, and self-reported salt limitation. Antihypertensive use for previously untreated mild hypertension is diverse. Older women with diastolic elevations who are health conscious are most likely to be treated.

Adolescent↗

PubMedDate not supplied

Characteristics of smokers who attempt to quit and of those who recently succeeded.

Although a high percentage of smokers attempt to quit each year, success rates are low. Thus, public health strategies must not only convince some smokers to attempt cessation, but also improve the success rate among other smokers already motivated to quit. Specific cessation strategies may be required for smokers in these two groups. This study compares sociodemographic and health behavior characteristics of smokers who have and have not attempted to quit and of those who recently succeeded. To determine whether these characteristics vary for men and women, we stratified analyses on gender. Data were obtained from random sample health surveys conducted 1981-1982 and 1983-1984 in two New England communities. Analyses include data on 2,086 respondents who reported smoking cigarettes in the previous year. Men and women were equally likely both to attempt cessation and to quit. Except for an inverse association with age, attempting to quit was not associated with sociodemographic variables. In men and women, attempts were associated with encouraging others to quit and attempting to increase exercise. Successful cessation attempts were associated with not living with a smoker in women; marital status, attempted weight loss, and increased age in men; and with efforts to increase exercise in both men and women. These characteristics could be useful in targeting smokers who attempt to quit, but fail. Improving the success rate in this group could greatly reduce smoking prevalence in the community.

Adult↗