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Biomedical subjects

S L Crawford

Publications and source records attributed to S L Crawford.

At least 19 recordsLinked to original sources
PubMed2002

Assessing menstrual cycles with urinary hormone assays.

The Study of Women's Health Across the Nation (SWAN) is a multiethnic cohort study of middle-aged women enrolled at seven US sites. A subset of 848 women completed a substudy in which their urinary gonadotropins and sex steroid metabolites were assessed during one complete menstrual cycle or up to 50 consecutive days. Urine was analyzed for LH, FSH, estrone conjugates (E1c), and pregnanediol glucuronide (Pdg). To prepare for serial analysis of this large, longitudinal database in a population of reproductively aging women, we examined the performance of algorithms designed to identify features of the normal menstrual cycle in midreproductive life. Algorithms were based on existing methods and were compared with a "gold standard" of ratings of trained observers on a subset of 396 cycles from the first collection of Daily Hormone Substudy samples. In evaluating luteal status, overall agreement between and within raters was high. Only 17 of the 396 cycles evaluated were considered indeterminate. Of the 328 cycles rated as containing evidence of luteal activity (ELA), 320 were considered ELA by use of a Pdg threshold detection algorithm. Of 51 cycles that were rated as no evidence of luteal activity, only 2 were identified by this algorithm as ELA. Evaluation of the day of the luteal transition with methods that detected a change in the ratio of E1c to Pdg provided 85-92% agreement for day of the luteal transition within 3 days of the raters. Adding further conditions to the algorithm increased agreement only slightly, by 1-8%. We conclude that reliable, robust, and relatively simple objective methods of evaluation of the probability and timing of ovulation can be used with urinary hormonal assays in early perimenopausal women.

Algorithms↗
PubMed2000

Self-defined menopausal status in a multi-ethnic sample of midlife women.

OBJECTIVES: This study aimed to identify factors associated with women's perceived menopausal status and to evaluate agreement between women's self-designation and a menstrually-based classification in a multi-ethnic sample of women. METHODS: A cross-sectional survey was conducted as part of a large, seven-site, multi-ethnic study, the Study of Women's Health Across the Nation (SWAN). All variables were assessed by self-report in 13952 women aged 40-55 years. Multiple linear regression was used to assess determinants of self-defined menopausal status, stratifying by race/ethnicity within three anatomical/hormone use strata. Kappa statistics were used to evaluate agreement between the self-defined and menstrually-based classifications. RESULTS: For women with an intact uterus, at least one ovary and not using hormones, menstrual patterns explained about half the variance in self-defined menopause status with older women classifying themselves later in the transition. Disagreement between menstrually-based and self-defined menopausal status was 39, 38, 36, 32 and 29% for Hispanic, African-American, Japanese, Caucasian, and Chinese women, respectively (kappa statistics=0.46, 0.41, 0.40, 0.53 and 0.58). Women with vasomotor symptoms tended to self-designate themselves as being in transition regardless of their menstrual patterns. Age and 12 months of amenorrhea explained about 40% of the variance in self-categorization among women using hormones with an intact uterus. Bilateral oophorectomy, age and time since surgery explained about 20% of the variance among post-surgical women. CONCLUSIONS: Menstrual characteristics are strong predictors of women's self-perceived menopausal status. However, additional factors, including symptoms and cultural differences in the meaning of specific bleeding patterns, are also relevant and require further investigation.

Adult↗
PubMed1999

Menstrual bleeding, hormones, and the menopausal transition.

The perimenopause represents a time of great variability in reproductive hormone dynamics and menstrual cycle characteristics, but age-related changes begin prior to this. These changes include a gradual increase in follicle stimulating hormone (FSH) levels, a gradual shortening of mean cycle length, and a decline in the number of ovarian follicles. The onset of perimenopause is thought to occur with the first break in menstrual cycle regularity. With the onset of cycle irregularities, hormone concentrations exhibit large increases in variability and unpredictability, rather than following a gradual trend with the approach of menopause, the final menstrual period. Abrupt spikes in gonadotropins and considerable fluctuations in estradiol and inhibin levels have been observed. Variability is the norm in the perimenopause, with hormonal fluctuations contributing to the visible signs of menstrual cycle and bleeding irregularities. To date there is no single endocrine indicator to serve as an adequate marker of menopausal status. This paper provides a review of research to date on patterns of reproductive hormones and menstrual bleeding during the menopausal transition. An understanding of such patterns can contribute to a better ability to distinguish "normal" transitional events from more serious pathology.

Adult↗
PubMed1998

The Health Belief Model and HIV risk behaviours: a causal model analysis among Anglos, African-Americans and Mexican-Americans.

A causal model of the Health Belief Model (HBM) is empirically evaluated which emphasizes possible indirect paths linking distal demographic and seriousness/susceptibility variables to HIV risk behaviours among Anglo, African-American, and Mexican-American adults. A specific focus of the paper is upon alcohol-related expectancies (anticipation of disinhibitory effects of alcohol upon sexual behavior) as a 'barrier' to preventive behaviours. Ethnic comparisons stem both from the paucity of available research on the HBM in minority populations and from recent questions regarding the applicability of rational models such as the HBM among minority groups. Analyses of data from a community sample of 1390 adults indicate relatively consistent direct effects of barriers for males and benefits for females upon HIV risk behaviors. The analyses suggest distinct paths operative among males and females. The susceptibility-barriers-risk behaviours path among males may suggest that alcohol-related expectancies (barriers in this model) may be more strongly related to risk behaviours among males than minority females.

Adult↗
PubMed1997

Interviewer effects in a cohort study. Results from the Massachusetts Women's Health Study.

Although interviewer error is widely recognized as an important source of variation in epidemiologic investigations, scant published information exists documenting the impact of interviewer variation on study findings. Using data from the Massachusetts Women's Health Study, a population-based cohort study of 2,569 middle-aged women (1982-1987), the authors evaluated interviewer variation in responses to different types of questions, and assessed the impact of interviewer variation on inferences derived from study data. Respondent sociodemographic and lifestyle characteristics were similar for the four study interviewers at the first follow-up. No interviewer variation was detected for questions concerning recall of specific events, but responses to questions regarding recall of subjective or personal information or those which required further probing did differ significantly by interviewer. Adjustment for interviewer effects had no impact on the conclusions obtained from one analysis of predictors of depression, despite significant interviewer variation in the outcome and predictor variables, but it did change conclusions from an analysis of the impact of support networks on psychological symptoms, wherein the interviewer variable was strongly related to the outcome after data were controlled for predictor variables. Given these findings, examination of data for interviewer effects is advisable despite incorporation of quality control measures in a study's design.

Depression↗
PubMed1997

Understanding the variability in the effectiveness of community heart health programs: a meta-analysis.

Over the past 25 years, community interventions to reduce cardiovascular disease (CVD) have been conducted around the world with very mixed results. This study uses meta-analysis to assess whether the variation in the observed effectiveness of community heart health programs (CHHP) is related to characteristics of the intervention program, the population under study, or the evaluation methods. A CHHP is defined as any primary prevention program that attempted to reduce the population burden of CVD by shifting the distribution of risk factors in a general population. To be included in the meta-analysis, a study must have utilized a reference group in the evaluation, employed a repeated independent cross-sectional measurement design, and reported sufficient outcome information for at least one of four major risk factors: smoking, total cholesterol, blood pressure, and body weight. Results of these studies are summarized with the effect size measure (Yi1-Yi2)-(Yr1-Yr2)Sr1 where Y = outcome measure, S = standard deviation of the outcome measure, 1 = baseline, 2 = follow-up. i = intervention, and r = reference community. This measure, which reports the net change in the intervention group in terms of the variability in the reference population before the start of the intervention, permits comparison across different outcome measures and facilitates the aggregation of effects across studies. Generalized least squares regression, which permits the incorporation of multiple, dependent effect sizes from a single study, was used to assess the impact of characteristics of the intervention (prevention strategy, type of mass communication, community organization, and environmental change), the population (setting, gender, year of follow-up measurement), and the evaluation design and implementation (the number of communities, matching of communities, the follow-up time, the response rate, and covariate adjustment in the analysis) on the effect sizes. The results of this analysis suggest that the characteristics of the evaluation method account for much of the heterogeneity in the outcome of CHHPs, though some intervention characteristics also play a role.

Blood Pressure↗
PubMed1997

Psychosocial, behavioral, and health factors related to menopause symptomatology.

Despite wide variation in the reporting of hot flashes and night sweats among menopausal women, what differentiates symptomatic from asymptomatic women is not well understood. In this article, we use longitudinal data from a large cohort of initially premenopausal women to address premenopausal factors predictive of length of the perimenopause, frequency of hot flash/night sweat (HF/NS) reporting, bothersomeness of HF/NS, and treatment seeking during menopause. The sample for analysis consists of 454 women from the Massachusetts Women's Health Study who were premenopausal at baseline and postmenopausal by the sixth and last study follow-up. Each of the four study outcomes was modeled as a function of premenopausal characteristics using logistic regression. Results confirm a wide range of symptom reporting, with 23% of women not reporting HF/NS at any of the six interviews. Variables related to greater frequency of HF/NS reporting included a longer perimenopause, more psychological and physical symptoms prior to menopause, lower education, and more negative attitudes toward menopause prior to menopause. Symptom bothersomeness was related to greater frequency of HF/NS reporting, smoking, and being divorced. Variables that predicted medical doctor consultation were greater frequency and bothersomeness of symptoms, higher education, and greater health care utilization. We conclude that general symptom reporting, attitudes toward menopause, and lifestyle factors can explain some of the individual variation in symptom reporting.

Attitude to Health↗
PubMed1996

Does collecting repeated blood samples from each subject improve the precision of estimated steroid hormone levels?

Measuring levels of steroid hormones in epidemiologic studies is difficult because pulsatile release can cause the levels of many hormones to vary markedly over short intervals, leading to a loss of precision in between-subject comparisons. Clinicians often control this variation by collecting several samples from each subject at defined intervals and pooling these samples for assay. The number of samples per subject that would adequately control such variation in an epidemiologic study has not been fully investigated. This study examines the effects of collecting 1, 2, or 3 samples per subject on the variances of 11 hormones and sex hormone binding globulin in men and 6 hormones in women. Three samples were collected at 30-minute intervals from each of 20 men and 59 women and were assayed separately. Variances that would be obtained in studies collecting one, two, or three samples per subject were then estimated. Collecting more than one sample substantially reduced the variances of several hormones in men but not in women.

Adult↗
PubMed1995

A comparison of anlaytic methods for non-random missingness of outcome data.

Missing outcome values occur frequently in survey data and are rarely missing randomly. Depending on the pattern of missingness, the choice of analytic method has implications for accuracy of the estimated outcome distribution as well as multivariate models. Data from a study of patterns of care in disabled elders were used to evaluate several common methods when missingness of the outcome was nonrandom. Results from single and multiple model-based imputation were compared with results from complete-case analysis and mean imputation. By ignoring nonrespondents' covariate information, the latter two methods yielded biased estimates of population means. Mean imputation and single model-based imputation underestimated standard errors by treating imputed values as if they were observed. Mean imputation also distorted the relationship between the outcome and predictors. Multiple model-based imputation provided an easily implemented method of adjustment for non-random non-response in both univariate and multivariate analyses.

Activities of Daily Living↗
PubMed1995

The everyday impacts of providing informal care to dependent elders and their consequences for the care recipients.

Longitudinal data were used to identify the relationship between different areas of negative impact and elder and caregiver characteristics. The extent and predictors of persistence and development of negative impact in different areas and the relationship between caregiving impact and subsequent caregiving patterns, including termination of care and institutionalization of the elder, were also examined. Caregiving exerted the greatest toll on a caregiver's personal life reported by 61%, in comparison to family life (18%), or employment (15%-20%). Those at particular risk of negative impact included offspring and other-relative caregivers who resided with the elder. All areas of negative impact persisted over time but did not result in any major disruption in care for the elder. However, those elders whose caregivers experienced personal impact were twice as likely to be institutionalized.

Aged↗
PubMed1994

Longitudinal patterns and correlates of hormone replacement therapy use in middle-aged women.

Patterns of hormone replacement therapy (HRT) use over time and predictors of initiating or discontinuing use were examined in a longitudinal study. A cohort of 2,425 women aged 45-55 years identified from a population-based random survey in Massachusetts in 1981-1982 was followed by six telephone interviews, 9 months apart. Cohort participants were either premenopausal (66.8%) or in early perimenopause (33.2%). During the study, prevalence of use was low overall (12.3%) and was considerably higher for surgical menopause (45%) than for peri- (9.3%), natural (4.5%), or premenopause (1.5%). Predictors of HRT uptake and discontinuation (from time t - 1 to time t) were examined by repeated-measures logistic regression, stratified by surgical status. For surgical menopause, the only significant predictor of HRT uptake was recent surgery (odds ratio = 4.4; 95% confidence interval 2.73-7.22), while for nonsurgical subjects, menopausal status (primarily perimenopause), prior use of HRT, health care utilization, hot flashes, alcohol consumption, regular exercise, and leaner body mass were all significant predictors of uptake. Discontinuing HRT was inversely associated with surgical and perimenopause and positively related to prior short-term use and health care utilization. Nonsurgical HRT users had a somewhat more favorable cardiovascular risk profile than did nonusers.

Climacteric↗
PubMed1994

Do characteristics of informal caregivers affect the length of hospital stay for frail elders?

Studies examining the length of hospital stay for the very old rarely include characteristics of the informal caregiver as potentially explanatory variables. This study expanded a frequently used conceptual model of health services use to include caregiving factors as enabling variables. Data were collected from a representative sample of frail elders who had been hospitalized in the previous 18 months (n = 181) and their primary informal caregivers. The findings indicate that elders whose primary caregiver was a coresiding offspring had shorter hospitalization than elders whose offspring caregiver lived in different households. These data indicate that the amount of variance explained by this conceptual model is increased when social factors are included as explanatory variables.

Adult↗
PubMed1994

Do blacks and whites differ in their use of health care for symptoms of coronary heart disease?

OBJECTIVES: The purpose of this study was to identify the role of race in seeking and receipt of care for symptoms of coronary heart disease. METHODS: Data on medical care, sociodemographic characteristics, symptoms, risk factors, income, and insurance were collected in a telephone interview for a random sample of 2030 Black and White adults in inner-city Boston. Rates of care-seeking for symptoms, amounts of delay in seeking care, and rates of receipt of care were compared for Blacks and Whites after adjustment for other characteristics. RESULTS: Before and after adjustment for other factors, Blacks and Whites were equally likely to seek care. Average delay time was shorter for Blacks, particularly Black women. With the exception of a lower rate of referral to cardiologists among Blacks, receipt of care was similar for Blacks and Whites who sought medical attention for symptoms. CONCLUSIONS: In an urban population of Blacks and Whites who were similar in socioeconomic status and access to medical care, there were few racial differences in coronary heart disease-related care patterns.

Black or African American↗
PubMed1993

HIV risk among Latino adolescents in two New England cities.

OBJECTIVES: Latino adolescents in two urban New England areas were surveyed to assess risk of human immunodeficiency virus (HIV) transmission. METHODS: Probability of HIV infection during the previous 6 months was estimated from self-reported sexual contacts, condom usage rates, and number of partners. Teens were also asked to show condoms in their possession to the interviewer to validate self-reports of condom use. RESULTS: Overall, 8% of the 586 respondents were classified as high risk for HIV infection (estimated infection probability greater than .0001), 34% were at moderate risk, and the remaining 58% were classified as not at risk (no sexual activity or needle sharing). Teens who said they had purchased condoms or claimed to have used them recently were more likely than others to have condoms in their possession at the time of the interview. CONCLUSIONS: These estimates suggest that a small percentage of Latino adolescents may be at substantial risk for HIV infection over periods as short as 6 months, that self-reports of recent condom use are strongly related to condom possession, and that questionnaire items regarding condom use at last intercourse are poor surrogates for HIV risk.

Adolescent↗
PubMed1993

Do blacks and whites differ in reporting Rose Questionnaire angina? Results of the Boston Health Care Project.

We investigated the prevalence of angina (as determined by the Rose Questionnaire) in a random sample of African-American and white adults, aged 44 to 75 years, in three Boston (Mass) neighborhoods. Telephone interviews were completed by 2030 eligible subjects (response rate = 87.9%). A sample of 737 persons who had never been hospitalized for a heart attack also participated in a home visit. The prevalence of Rose angina was 7.0% in black women, 4.8% in white women, 5.0% in black men, and 5.7% in white men (P = .37). In both racial groups, respondents with diagnosed cardiovascular conditions, those taking cardiovascular medications, and those living alone were more likely to report angina than were other respondents. Blacks were more likely to report angina if they felt they were not getting needed medical care. Risk of angina declined with age among whites. In the home visit sample, the presence of major electrocardiogram abnormalities was also associated with angina. Rose angina appears to be influenced by similar risk factors in both blacks and whites.

Adult↗
PubMed1993

Is family care on the decline? A longitudinal investigation of the substitution of formal long-term care services for informal care.

The focus on rising costs of long-term care now encompasses community as well as institutional care. Policy makers cite the potential impact of changing social trends on informal caregivers' availability to continue as the main source of care and the possibility that formal services will then replace this informal care. They fear that families will relinquish their caregiving role if publicly funded home care services are available. Longitudinal data from a sample of disabled elders were used to investigate the substitution of formal services for informal care over a seven-year period. The substitution that was detected could be traced to the limited availability of informal care, and it represented a temporary change in the informal care pattern rather than a permanent replacement for it. Instead, use of formal services has supported the elderly person's continued residence in the community.

Aged↗
PubMed1993

Job stress and occupational health nursing: modeling health affirming choices.

1. Job stress is a condition or event in the workplace that induces strain (a physical, psychological, or behavioral response to a stressor). The outcome of unrelieved job stress can be burnout. 2. Occupational health nurses can experience job stress in the areas of intrinsic job factors, organizational structures, reward systems, human resource systems, and leadership. 3. Stress reduction techniques can be grouped into physical, social, spiritual, intellectual, emotional, and environmental strategies. 4. Application of stress reduction strategies to reduce experienced job stress in occupational health nurses is one way occupational health nurses can model health affirming choices.

Adaptation, Psychological↗