Correlation and regression.
Explore the source record for details and available documents.
Least-Squares Analysis↗
Biomedical subjects
Sybil L Crawford
Publications and source records attributed to Sybil L Crawford.
Vasomotor symptom prevalence is associated with polymorphisms in sex steroid-metabolizing enzymes and receptors.
The relation of single nucleotide polymorphisms (SNPs) of genes involved in estrogen function to vasomotor symptoms (VMS) has been inadequately explored. We evaluated SNPs in sex steroid-metabolizing genes and estrogen receptors (ERs) for their association with VMS (hot flashes, night sweats, and/or cold sweats) reported by women who were premenopausal or in early perimenopause at baseline. The study population was drawn from participants in the Study of Women's Health Across the Nation (SWAN). African American, Caucasian, Chinese, and Japanese women, 42 to 52 years of age at baseline, who were enrolled in the longitudinal, community-based cohort of SWAN provided questionnaire, interview, weight and height measurements, and serum samples through the sixth annual visit. SNPs associated with the sex steroid hormone pathway were genotyped and available for 1,538 participants. These SNPs were associated with reporting VMS > or =6 days compared with <6 days in the past 2 weeks using race/ethnicity-specific repeated measures logistic regression models. Participants were on average 46 years old at baseline. The prevalence of VMS reporting increased in all racial/ethnic groups from baseline to the sixth annual follow-up visit. After adjustment for covariates, several SNPs encoding genes responsible for estrogen metabolism and ERs were associated with decreased odds of reporting VMS, including the CYP1B1 rs1056836 GC genotype in African American women; 17HSD rs615942 TG, 17HSD rs592389 TG, and 17HSD rs2830 AG genotypes in Caucasian women; and the CYP1A1 rs2606345 AC genotype in Chinese women. We identified race/ethnicity-specific associations between VMS reporting and specific polymorphisms for sex steroid-metabolizing enzymes and sex steroid receptors. Clarification of the mechanisms of the associations and confirmation in other populations is warranted.
17-Hydroxysteroid Dehydrogenases↗
Use of a flow-mediated vasodilation technique to assess endothelial function in dogs.
OBJECTIVE: To develop and assess the reproducibility of a protocol to noninvasively test endothelial function in dogs on the basis of the flow-mediated vasodilation (FMD) procedure used in humans. ANIMALS: 5 healthy spayed female dogs. PROCEDURES: Luminal arterial diameter and blood flow velocity in the brachial and femoral arteries were measured with ultrasonography. The within-dog reproducibility of these ultrasonographic measurements was tested. An occlusion period of 1, 3, or 5 minutes with an inflatable cuff was used to create the FMD response. Measurements made at 15, 30, and 60 seconds following release of the occlusion were compared with measurements made immediately prior to each occlusion to assess the FMD response. RESULTS: Within-dog reproducibility of measurements revealed moderate to high correlations. Change from baseline in luminal arterial diameter was most substantial when measured at 30 seconds following release of occlusion, whereas blood flow velocity changes were maximal when measured at 15 seconds following release. The brachial imaging site provided a larger number of significant FMD responses than the femoral site. The 3-minute occlusion period provided equal or better responses than the 5-minute occlusion period. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonographic measurement of the FMD responses was a feasible and reproducible technique and significant changes from baseline were detected. The FMD responses in dogs were most substantial when performed at the brachial artery with blood flow velocity and luminal arterial diameter changes from baseline measured at 15 and 30 seconds, respectively, following release of a 3-minute occlusion period.
Animals↗
Ethnic differences in cardiovascular risk factor burden among middle-aged women: Study of Women's Health Across the Nation (SWAN).
BACKGROUND: We evaluated ethnic differences in the 10-year risk of myocardial infarction or coronary death derived from Framingham risk equation and in a composite measure of emerging cardiovascular disease risk factors in women and whether statistical adjustments for educational attainment, geographic location, and lifestyle attenuated the magnitude of the ethnic differences in risk. METHODS: Two thousand eight hundred thirty-four premenopausal women free of stroke, heart disease, or diabetes and aged of 42 to 52 years (1400 whites, 729 African American, 226 Hispanic, 231 Chinese, and 248 Japanese) had measurements of blood pressure, lipids and lipoproteins, waist circumference, glucose, insulin, lipoprotein(a), fibrinogen, factor VII, plasminogen activator inhibitor, tissue-type plasminogen activator antigen, and high-sensitivity C-reactive protein. Framingham risk score and number of risk factors in the top quartile of the distribution of risk factors not included in the Framingham score (called composite burden) were calculated. RESULTS: The unadjusted mean values for the two summary scores were higher among African Americans and Hispanics than other groups. Statistical adjustments for education and geographical site accounted for a majority of the ethnic differences, with an additional small effect of lifestyle for the composite burden score. Largest ethnic differences were apparent for waist circumference, lipoprotein(a), high-sensitivity C-reactive protein, and untreated blood pressure. CONCLUSIONS: A substantial part of the risk associated with ethnicity can be attributed to socioeconomic status and geographical location. As the ethnic composition of the United States population becomes more diverse, it is important to appreciate the cardiovascular disease risk factor burden present in some minority groups.
Adult↗
Association of lipoprotein(a), insulin resistance, and reproductive hormones in a multiethnic cohort of pre- and perimenopausal women (The SWAN Study).
Because evidence suggests lipoprotein (Lp(a)) may be an important cardiovascular risk factor in women, we evaluated whether reproductive hormones may influence Lp(a) concentrations and insulin resistance in a large multicenter study of women transitioning to postmenopause. Data were taken from the Study of Women's Health Across the Nation (SWAN), a prospective multiethnic study of menopausal transition (1,368 Caucasians, 808 African-Americans, 220 Chinese, 216 Hispanic, and 251 Japanese). Blood was assayed for Lp(a), follicle stimulating hormone, estradiol (E2), testosterone, and sex hormone binding globulin (free estradiol index and free androgen index), thyroid stimulating hormone, and glucose and insulin (to calculate insulin resistance). African-American women had twofold higher mean Lp(a) values than women of the other 4 race/ethnic groups, adjusted for body mass index (BMI). Lp(a) was modestly correlated with E2 (r = 0.10) in women without self-reported diagnosed heart disease but not in women with self-reported heart disease. Lp(a) was positively associated with log insulin resistance in women without self-reported heart disease but not in women with self-reported heart disease, an association that was not significant after adjusting for ethnicity, BMI, smoking, age, and site. Race/ethnicity, particularly being African-American, accounted for most of the explained Lp(a) variations. Lp(a) was very modestly associated (r = -0.04) with insulin resistance after adjusting for ethnicity and BMI, and this association was not modified by reproductive hormones, including androgens.
Adult↗
Employment and caregiving: exploration of African American caregivers.
To more completely understand the challenges African American families face when combining employment commitments and informal caregiving responsibilities, the authors used data from a community sample of 119 African American elder-caregiver dyads. This article examines the nature of caregiving relationships and extent to which caregivers' employment statuses affect the hours of care provided. The authors concluded that employed caregivers do not provide significantly less care than do unemployed caregivers, elderly people with employed caregivers are no more likely than those with unemployed caregivers to use formal services, and unemployed caregivers may remain unemployed partly because of caregiving responsibilities.
Black or African American↗
Chronic disease medication use in managed care and indemnity insurance plans.
OBJECTIVE: To evaluate the impact of managed care on the use of chronic disease medications. DATA SOURCE: Claims data from 1997 from two indemnity and three independent practice association (IPA) model managed care insurance plans. RESEARCH DESIGN: Cross-sectional analysis of claims data. DATA COLLECTION: Adult patients with diabetes mellitus (DM, n = 26,444), congestive heart failure (CHF, n = 7,978), and asthma (n = 9,850) were identified by ICD-9 codes. Chronic disease medication use was defined through pharmacy claims for patients receiving one or more prescriptions for drugs used in treating these conditions. Using multiple logistic regression we adjusted for patient case mix and the number of primary care visits. PRINCIPAL FINDINGS: With few exceptions, managed care patients were more likely to use chronic disease medications than indemnity patients. In DM, managed care patients were more likely to use sulfonylureas (43 percent versus 39 percent for indemnity), metformin (26 percent versus 18 percent), and troglitazone (8.8 percent versus 6.4 percent), but not insulin. For CHF patients, managed care patients were more likely to use loop diuretics (45 percent versus 41 percent), ACE inhibitors or angiotensin receptor blockers (50 percent versus 41 percent), and beta-blockers (23 percent versus 16 percent), but we found no differences in digoxin use. In asthma, managed care patients were more likely to use inhaled corticosteroids (34 percent versus 30 percent), systemic corticosteroids (18 percent versus 16 percent), short-acting beta-agonists (42 percent versus 33 percent), long-acting beta-agonists (9.9 percent versus 8.6 percent), and leukotriene modifiers (5.4 percent versus 4.1 percent), but not cromolyn or methylxanthines. Statistically significant differences remained after multivariate analysis that controlled for age, gender, and severity. CONCLUSIONS: Chronic disease patients in these managed care plans are more likely to receive both inexpensive and expensive medications. Exceptions included older medications partly supplanted by newer therapies. Differences may be explained by the fact that patients in indemnity plans face higher out-of-pocket costs and managed care plans promote more aggressive medication use. The relatively low likelihood of condition-specific medications in both plan types is a matter of concern, however.
Adult↗
Assessment of digit preference in self-reported year at menopause: choice of an appropriate reference distribution.
Estimated associations between self-reported age at menopause and health may be attenuated if self-report is inaccurate. In a cross-sectional study, it is not possible to assess validity or reproducibility. Instead, one can examine digit preference, e.g., overreporting of numbers ending in zero or five. Typically, analyses use equal proportions-10% probability for each digit-as the reference distribution. Depending on the age distribution of the sample and on the underlying distribution of age at the event, however, an alternative reference distribution may be more appropriate. As an illustration, the authors examined digit preference in the self-reported calendar year at the final menstrual period in cross-sectional data from 2,151 naturally postmenopausal women in the Study of Women's Health Across the Nation (1995-1997), a multisite, multiethnic study of women aged 40-55 years. With chi-square tests, the distribution of terminal digit for self-reported year at the final menstrual period was compared with several reference distributions. The observed distribution was much closer to a reference distribution based on previously published data than it was to equal proportions. Future assessments of digit preference in cross-sectional studies should consider alternatives to equal proportions, particularly for samples with small age ranges and events with a restricted underlying age distribution.
Adult↗
Help-seeking behaviors of blacks and whites dying from coronary heart disease.
OBJECTIVES: This study sought to determine whether blacks and whites with life-threatening cardiac events differ in likelihood of help seeking, types of help sought, or likelihood of reaching the hospital before death. DESIGN: Death certificates were used to identify all coronary heart disease-related deaths occurring in 1988-89 among 45- to 74-year-old, black and white, non-institutionalized residents of three contiguous inner-city districts in Boston, Massachusetts, USA. An informant was interviewed about the decedent's health status, access to care and pre-mortal help-seeking behaviors. RESULTS: Among the 232 decedents analyzed, there were no racial differences in the likelihood of help seeking. Among those who sought help, there were no racial differences in the likelihood of reaching the hospital. However, blacks were more likely than whites to engage in two specific help-seeking behaviors: calling the 911 emergency system, and trying to reach an emergency room. CONCLUSION: In an area where blacks and whites were similar with respect to socioeconomic status and access to care, race did not affect the likelihood of help seeking or the likelihood of succeeding in reaching the hospital before death.
Black or African American↗