Biomedical subjects

M F Sowers

Publications and source records attributed to M F Sowers.

At least 19 recordsLinked to original sources

PubMed2003

Magnetic resonance-detected subchondral bone marrow and cartilage defect characteristics associated with pain and X-ray-defined knee osteoarthritis.

OBJECTIVE: To assess whether the presence of subchondral bone marrow abnormalities (bone marrow edema (BME)) and cartilage defects, determined by magnetic resonance imaging (MRI), would explain the difference between painful osteoarthritis of the knee (OAK) compared with painless OAK or pain without OAK. METHOD: Four groups of women (30 per group), aged 35-55 years, were recruited from the southeast Michigan Osteoarthritis cohort (group 1: painful OAK; group 2: painless OAK; group 3: knee pain without OAK; and group 4: no OAK or knee pain). OAK was defined by a Kellgren-Lawrence score of 2 or greater, while pain was based on self-report. BME and cartilage defects were identified from MRI. RESULTS: BME lesions were identified in 56% of all knees. BME lesions were four times (95% CI=1.7, 8.7) more likely to occur in the painless OAK group as compared with the group with pain, but no OAK. BME lesions >1cm were more frequent (OR=5.0; 95% CI=1.4, 10.5) in the painful OAK group than all other groups. While the frequency of BME lesions was similar in the painless OAK and painful OAK groups, there were more lesions, >1cm, in the painful OAK group. About 75% of all knees had evidence of some cartilage defect, of which 35% were full-thickness defects. Full-thickness cartilage defects occurred frequently in painful OAK. One-third of knees with full-thickness defects and 47% of knees with cartilage defects involving bone had BME >1cm. Women with radiographic OA, full-thickness articular cartilage defects, and adjacent subchondral cortical bone defects were significantly more likely to have painful OAK than other groups (OR=3.2; 95% CI=1.3, 7.6). CONCLUSION: The finding on MRI of subchondral BME cannot satisfactorily explain the presence or absence of knee pain. However, women with BME and full-thickness articular cartilage defects accompanied by adjacent subchondral cortical bone defects were significantly more likely to have painful OAK than painless OAK.

Adult↗

PubMed2003

Premature menopause in a multi-ethnic population study of the menopause transition.

BACKGROUND: Premature menopause, also termed premature ovarian failure (POF), is characterized by cessation of menstruation before the age of 40 years. Little information is available on the general prevalence of POF or on the prevalence by ethnic group. There is also a lack of information on the association of POF with health indicators. METHODS: A cross-sectional survey of women aged 40-55 years was conducted at seven sites in the USA to determine eligibility for a community-based, multi-ethnic longitudinal study of the peri-menopause (The Study of Women Across the Nation, SWAN). Interview data were used to (i). determine the prevalence of self-reported POF overall and by ethnic group, and (ii). assess the association of POF with selected self-reported variables related to health. Cases of POF included only women with no discernible cause for POF. RESULTS: POF was reported by 1.1% (126/11 652) of women. By ethnicity, 1.0% (95% CI, 0.7-1.4) of Caucasian, 1.4% (95% CI, 1.0-2.1) of African American, 1.4% (95% CI, 0.8-2.5) of Hispanic, 0.5% (95% CI, 0.1-1.9) of Chinese and 0.1% (95% CI, 0.02-1.1) of Japanese women experienced POF. The differences in frequency across ethnic groups were statistically significant (P = 0.01). Only Caucasian, African American and Hispanic women were included in further analyses since too few Asian women had POF. In a multivariate model, POF was independently associated with osteoporosis, female hormone use (excluding oral contraceptives), higher body mass index (BMI) and current smoking after adjustment for education level, ability to pay for basics, site and age at interview. In Caucasian women, use of female hormones, osteoporosis, severe disability and smoking were significantly associated with POF. In contrast, POF in African American women was associated with higher BMI and female hormone use, but not osteoporosis. CONCLUSIONS: The prevalence of POF appears to vary by ethnicity. Health factors associated with POF also vary by ethnicity but because of the cross-sectional study design, it is not possible to determine cause and effect relationships. Health risks of POF would benefit from further study.

Adult↗

PubMed2002

Natural history of bone loss over 6 years among premenopausal and early postmenopausal women.

The aims of this prospective cohort study were to determine rates of premenopausal and early postmenopausal bone loss, age at onset of bone loss, and whether rates of bone loss depend on baseline bone mineral density (BMD). The cohort of 614 women aged 24-44 years at baseline from the longitudinal Michigan Bone Health Study was followed for 6 years beginning in 1992-1993. Up to five BMD measurements of the lumbar spine (L(2-4)) and the femoral neck were obtained through 1998-1999 by using dual x-ray absorptiometry and were standardized (as z scores) relative to a young adult, female BMD distribution. Regression models were used to estimate rates of BMD change and to examine BMD as a function of age. At the lumbar spine, the rate of BMD change for premenopausal women varied with time. At the femoral neck, the rate of change was -1.6% (95% confidence interval: -0.9%, -2.3%) of a z score annually (annual loss of 0.3% of baseline BMD (g/cm(2))). Evidence for age at onset of bone loss at the lumbar spine was inconclusive. Bone loss began by the midtwenties at the femoral neck. Additional annual change of -0.7% (95% confidence interval: -0.2%, -1.2%) of a z score was observed at the femoral neck for each unit increase in BMD z score at baseline.

Absorptiometry, Photon↗

PubMed2002

Improving the assessment of gestational age in a Zimbabwean population.

OBJECTIVES: To evaluate the performance and the utility of using birthweight-adjusted scores of Dubowitz and Ballard methods of estimating gestational age in a Zimbabwean population. METHOD: The Dubowitz and the Ballard methods of estimating gestational age were administered to 364 African newborn infants with a known last menstrual period (LMP) at Harare Maternity Hospital. RESULTS: Both methods were good predictors of gestational age useful in differentiating term from pre-term infants. Our regression line was Y((LMP gestational age))=23.814+0.301*score for the Dubowitz and Y((LMP gestational age))=24.493+0.420*score for the Ballard method. Addition of birthweight to the regression models improved prediction of gestational age; Y((LMP gestational age))=23.512+0.219*score+0.0015*grams for Dubowitz and Y((LMP gestational age))=24.002+0.292*score+0.0016*grams for Ballard method. CONCLUSIONS: We recommend the use of our birthweight-adjusted maturity scales; the Dubowitz for studies of prematurity, and the Ballard for routine clinical practice.

Adolescent↗

PubMed2002

The natural history of emergent osteoarthritis of the knee in women.

OBJECTIVE: We assessed the probability that mid-aged women with a Kellgren and Lawrence (K-L) score of 1 are likely to progress to a score of 2 or regress to a score of zero at a second time point, 2-3 years later. METHODS: Osteoarthritis (OA) of measurements (weight-bearing X-rays and interviews) were undertaken in women from the Southeast Michigan population who were > or =40 years of age, and who participated in both the 1995 and 1998 measurements (N=679). RESULTS: Of the 17.1 % of women with a 1995 K-L score of 1 in their right knee, 37.1% had a K-L score of 1 in 1998 while 32.8 % had a score of > or =2 and 30.2% had a score of zero. For 26.0% of women, the score progressed by at least one unit over the 2.5 year period whereas scores for only 7.0% of women regressed in the same time period. Women who had a K-L score of 1 in the right knee in 1995 were 2.5 times more likely to have a K-L score of 1 in 1998 (95% CI=1.6-3.8); and were 2.2 times more likely to have a K-L score of 2 or greater (95% CI=1.4-3.5) in 1998 compared with other scores. These women were 74% less likely to have a score of zero in 1998 (95% CI=0.2-0.4). Further, other risk factors, specifically age and BMI were predictors of increasing K-L grade in 1998. CONCLUSION: These findings suggest that a score of 1 is part of the advancement to emergent OAK; and suggest the following criteria to characterize individuals who are at an intervenable stage on the pathway toward OAK: age > or =40, BMI > or =30, and K-L score of > or =1. From the perspective of both the individual and the examiner, these assessment characteristics are relatively simple to assess clinically.

Adult↗

PubMed2001

Testosterone concentrations in women aged 25-50 years: associations with lifestyle, body composition, and ovarian status.

While there is substantial evidence of the importance of endogenous and exogenous estrogen in reproductive health and chronic disease, there is little consideration of androgens in women's health. In the Michigan Bone Health Study (1992-1995), the authors examined the correlates of testosterone concentrations in pre- and perimenopausal women (i.e., age, menopausal status, body composition, and lifestyle behaviors) in a population-based longitudinal study including three annual examinations among 611 women aged 25-50 years identified through a census in a midwestern community. Current smokers had the highest testosterone concentrations with decreasing values in former and nonsmokers (p = 0.0001). Body composition measures (body mass index, body fat (%), weight (kg), lean body mass (kg), and fat mass (kg)) were significantly and positively associated with total testosterone concentrations in a dose-response manner. Hysterectomy with oophorectomy was associated with significantly lower testosterone concentrations. Alcohol consumption, physical activity, and dietary macronutrient intake were not associated with testosterone concentrations. This is one of the first studies to examine correlates of serum testosterone concentrations in anticipation of the growing interest in the role of androgens in women's health. The greater circulating levels of testosterone in obese women and smokers suggest that testosterone concentrations should be considered in the natural history of disease conditions where obesity and smoking are risk factors, including cardiovascular disease.

Adult↗

PubMed2000

The menopause transition and the aging process: a population perspective.

The menopause transition period, extending from active reproductive capacity with well-characterized hormone profiles through reproductive senescence, has been less well studied than any other period of the life span except extreme old age. Yet, for the gerontologist, this is an important period to understand for at least two reasons. First, during this period changes in the neuroendocrine system and ovary may provide a model for the study of other aging-related processes. Second, specific characteristics of this transitional period (including duration, intensity, and age at menopause) may be considered "aging", and influence short-term health and quality-of-life status, as well as life expectancy. In addition to discussing the menopause transition in terms of age and culture, we include some of the theories and conceptual models that can influence the nature and interpretation of information from this time period, and its ultimate impact on health and health practice.

Aging↗

PubMed2000

Bone loss in adolescent and adult pregnant women.

OBJECTIVE: To determine the amount of change in bone ultrasound measures among pregnant adolescent girls and women and whether that change was associated with adolescence, maternal growth during pregnancy, limited weight gain during pregnancy, hypertension in pregnancy, or poor diet. METHODS: We used bone ultrasound measurements of attenuation and sound velocity to assess changes in quantitative ultrasound indices of 252 pregnant adolescent girls and women age 12-34 years. Bone ultrasound measurement of the os calcis was performed at 16 +/- 7 weeks' gestation (mean +/- standard deviation and 6 +/- 1 weeks postpartum. RESULTS: On average, the bone quantitative ultrasound index was 3.6% lower 6 weeks postpartum than at entry into care (P <.001). Nulliparous patients had significantly greater bone loss than did parous subjects. Still-growing adolescents had greater quantitative ultrasound index decreases than did grown women (-5.5% versus -1.9%, P <.02). Patients in the upper tertile of baseline quantitative ultrasound index lost more bone than did patients in the lower tertile (-5% versus 0.5%, P <.02). Pregravid weight, weight change during pregnancy, gynecologic age, and age at menarche predicted bone change in subgroups defined by parity or age; however, none of the differences in those variables were statistically significant. Greater dietary calcium intake, less physical activity, and pregnancy hypertension and preeclampsia were not associated with bone change. CONCLUSION: There has been inconsistent evidence of maternal bone loss during pregnancy. The findings of this study challenge the assumption that because of increased calcium absorption from the maternal intestine, no transitory bone loss occurs in pregnancy. The amount of bone loss among growing adolescents and nulliparous patients was consistent with the demands of fetal mineralization and the continued demands of the maternal skeleton during growth.

Adolescent↗

PubMed2000

Lower peak bone mass and its decline.

There is evidence that two-thirds of the risk of osteoporotic fracture can be predicted from the pre-menopausal bone mineral density. The frequency of osteoporosis in older women may be modifiable by implementing invention strategies in the pre- and peri-menopausal periods. Lower peak bone mineral density and bone loss can be identified in women with altered reproductive hormone or calciotrophic hormone concentrations, or selected lifestyle practices. Alterations in reproductive hormones may occur in adolescence (from an early age of pregnancy or the amenorrhoea of anorexia nervosa or exercise), in the pre-menopause (nulliparity, oophorectomy, early ovarian failure or marginal hormonal status) or in the peri-menopause. Alterations in calciotrophic hormone concentrations include corticosteroid therapy and breast cancer treatment. Lifestyle risk factors include the misuse of alcohol and possibly smoking, physical inactivity or an imbalance in dietary intake. Effective intervention currently consists of treating underlying conditions and monitoring high-risk groups.

Aging↗

PubMed1999

The effect of weight cycling on blood lipids and blood pressure in the Multiple Risk Factor Intervention Trial Special Intervention Group.

OBJECTIVE: To assess whether weight cycling has adverse effects on blood lipids or blood pressure. DESIGN: Cohort study, six years of follow-up, comparing net change in blood lipids and blood pressure among weight cyclers and non-cyclers. SUBJECTS: Men (n = 4353), age 35-57 y, at high risk for heart disease because of smoking, high blood pressure, and elevated cholesterol concentration in the Multiple Risk Factor Intervention Trial (MRFIT)--a 22-site, multi-center collaborative primary prevention trial conducted in the US, 1973-1983. MEASUREMENTS: A weight cycle was defined as loss and regain of at least 5% of mean weight. Outcome measures were changes from baseline to year six in total serum cholesterol, high density lipoprotein cholesterol (HDL), the ratio of total cholesterol to HDL, and diastolic blood pressure. ANALYSIS: Analysis of covariance models were developed, with number of weight cycles as the predictor variable. The hypothesis was that men who weight cycled would experience less improvement in blood lipids and blood pressure than those who did not cycle. Adjustments were made for net weight change and other factors affecting each outcome. RESULTS: Men who weight cycled did not have the predicted smaller improvements in total cholesterol, HDL, the ratio of total cholesterol to HDL, or diastolic blood pressure, compared with noncyclers. CONCLUSION: An adverse effect of weight cycling on blood pressure or blood lipids was not found. The excess mortality previously reported among weight cyclers in this population can probably not be attributed to effects on these CVD risk factors.

Adult↗

PubMed1996

Elevated parathyroid hormone-related peptide associated with lactation and bone density loss.

OBJECTIVE: To investigate the hypothesis that parathyroid hormone-related peptide (PRHrP) may be involved with bone loss and recovery as a means of providing adequate calcium and phosphate to infants. DESIGN: An 18-month prospective cohort study. SETTING: General community setting with recruitment occurring at birthing education classes. PARTICIPANTS: Volunteer sample of 115 postpartum healthy women aged 20 to 40 years, and 0 or 1 parity prior to parturition with no intent to breast-feed or intent to breast-feed at least 6 months. MAIN OUTCOME MEASURES: Parathyroid hormone-related peptide, prolactin, estradiol, 1,25-dihydroxyvitamin D, 24-hydroxyvitamin D, femoral bone mineral density, and bone turnover markers were measured in 115 postpartum women at 2 weeks, 2 months, 4 months, 6 months, 12 months, and 18 months postpartum. Lumbar bone mineral density was measured at 2 weeks, 6 months, 12 months, and 18 months postpartum. RESULTS: Elevated PTHrP values were significantly associated (P<.001) with breast-feeding status, elevated prolactin levels, and lower serum estradiol levels, conditions occurring during lactation. Furthermore, elevated PTHrP levels were negatively and significantly associated (P<.01) over time with bone mineral density change at both the spine and the femoral neck, even after accounting for prolactin levels, breast-feeding status, return of menstruation, estradiol levels, PTH levels, 1,25-dihydroxyvitamin D levels, dietary calcium intake, physical activity, and body size. CONCLUSION: These data clearly support the hypothesis that PTHrP is an alternative mechanism associated with bone loss and recovery during and subsequent to lactation.

Absorptiometry, Photon↗

PubMed1996

Association of bone mineral density and sex hormone levels with osteoarthritis of the hand and knee in premenopausal women.

Mechanical stress on the cartilage and metabolic and/or hormonal influences have been suggested as possible etiologic factors for osteoarthritis. This paper reports findings from data collected in 1992 that were used to examine associations between osteoarthritis and risk factors in 573 Caucasian women aged 24-45 years from the Michigan Bone Health Study. Radiographs of the dominant hand and both knees were evaluated using the Kellgren and Lawrence grading scale. The prevalence of osteoarthritis (grade 2 or higher) in this population was 2.8% for hands and 3.6% for knees. Using polytomous multiple logistic regression, the authors found older age, increasing bone mineral density, and decreasing testosterone levels to be significantly associated with increasing hand scores. Older age and hand injury were significantly associated with grades of 2 or higher. Increasing osteoarthritis knee scores were associated with older age, increasing bone density, increasing body mass index, and current use of hormone replacement therapy. A knee grade of 2 or higher was associated with increasing estradiol levels, knee injury, and higher blood pressure. This study indicates that age, bone density, and injury are risk factors common to the development of hand and knee osteoarthritis in this non-elderly female population.

Adult↗

PubMed1992

Joint influence of fat and lean body composition compartments on femoral bone mineral density in premenopausal women.

Body composition (fat and lean compartments) and bone mineral density were measured in 246 healthy premenopausal women, aged 20-40 years, residing in Tecumseh, Michigan. Body composition was measured using four-point bioelectrical impedance and values for fat and lean compartments categorized into tertiles. Additionally, each woman was classified into one of nine different cells based on her location within a 3 x 3 table which reflects the joint distribution of both fat and lean compartments. Bone mineral density of the proximal femur, including the femoral neck and trochanter, was measured using dual photon densitometry. The mean femoral neck bone mineral density values increased significantly and linearly for each tertile of muscle mass (0.90, 0.95, and 1.02 g/cm2, p less than 0.0002). Femoral bone mineral density increased significantly but not linearly as the fat compartment progressed from the lowest to the highest tertile (0.95, 0.93, and 0.99 g/cm2). Bone mineral density of the proximal femur was similar and significantly greater in the high muscle/low fat and high muscle/high fat body composition subgroups compared with bone mineral density in the seven other groups. However, women in the high muscle/low fat subgroup had substantially lower mean weight (67 vs. 91 kg, p less than 0.0001) and mean Quetelet index (22.1 vs. 33.7 kg/m2, p less than 0.0001) than women in the high muscle/high fat subgroup. Bone mineral density values were similar and significantly lower in the following body composition cells: low muscle/low fat, low muscle/medium fat, and low muscle/high fat. Similar findings were observed at the trochanteric site. Low muscle is a risk factor for low bone mineral density in young adult women while higher fat is protective only when associated with substantial muscle.

Absorptiometry, Photon↗

PubMed1992

Sources of fiber and fat in diets of US women aged 19 to 50: implications for nutrition education and policy.

INTRODUCTION: Many women are not meeting dietary recommendations for fiber and fat intakes. Health educators need to know which foods are major sources of these nutrients. METHODS: This study analyzed the contributions of 27 food groups to fiber, fat, saturated fat, and cholesterol intakes of 2134 women aged 19 to 50 years in USDA's Continuing Survey of Food Intakes by Individuals, the 1985 and 1986 surveys (CSFII 85-86). RESULTS: Major determinants of fiber intake include frequency of use of certain food groups (vegetables, including potatoes, bread, fruit, soups, ready-to-eat cereal) and choice of particular foods within the larger food groups (e.g., whole grain bread, high fiber cereal). Major determinants of total fat, saturated fat, and cholesterol intakes included frequency of use of certain foods (sweet grains, beef, eggs, cheeses/cream, whole milks) and additions to foods (regular salad dressing and butter/margarine). Demographic characteristics were related to various food group consumption parameters. CONCLUSIONS: Information about the relationships between food group and nutrient intake and the effects of household income, race/ethnicity, and region of residence on food group intake indicate opportunities to refine nutritional education programs.

Adult↗

PubMed1991

A prospective study of bone mineral content and fracture in communities with differential fluoride exposure.

In 1983/1984, a study of bone mass and fractures was begun in 827 women aged 20-80 years in three rural Iowa communities selected for the fluoride and calcium content of their community water supplies. The control community's water had a calcium content of 67 mg/liter and a fluoride content of 1 mg/liter. The higher-calcium community had water with a calcium content of 375 mg/liter and a fluoride content of 1 mg/liter. The higher-fluoride community's water had 15 mg/liter of calcium and 4 mg/liter of fluoride naturally occurring. In 1988/1989, a follow-up study characterized the 684 women still living and available for study. Residence in the higher-fluoride community was associated with a significantly lower radial bone mass in premenopausal and postmenopausal women, an increased rate of radial bone mass loss in premenopausal women, and significantly more fractures among postmenopausal women. There was no difference in the 5-year relative risk of any fracture in the higher-calcium community versus the control community; however, the relative risk was 2.1 (95% confidence interval (CI) 1.0-4.4) in women in the higher-fluoride community compared with women in the control community. There was no difference in the 5-year risk of wrist, spine, or hip fracture in the higher-calcium community versus the control community; however, the 5-year relative risk for women in the higher-fluoride community, compared with women in the control community, was 2.2 (95% CI 1.1-4.7). Estimates of risk were adjusted for age and body size.

Adult↗

PubMed1990

Retinol, supplemental vitamin A and bone status.

Studies of hypervitaminosis A in animals and anecdotal reports of accidental vitamin A poisoning in humans suggest impairment of bone remodeling and increased numbers of fractures. Because of the widespread use of high-dose vitamin A supplements which may produce subclinical hypervitaminosis associated with decreased bone mass and increased risk of fracture, we studied the relationship between current vitamin A supplement use, serum retinol levels, radial bone mass and fracture history in a geographically-defined population of 246 postmenopausal women, 55-80 years of age. More than 36% of this population used a vitamin A supplement with 8% of these consuming an amount in excess of 2000 retinol equivalents (RE)/day. Serum retinol was measured using high-pressure liquid chromatography and radial bone mass was measured using single photon absorptiometry. After controlling for age, current estrogen replacement, and current thiazide antihypertensive use, we observed no statistically significant relationship between vitamin A supplement use or serum retinol with radial bone mass or fractures.

Adult↗

PubMed1988

Relationship between 1,25-dihydroxyvitamin D and blood pressure in a geographically defined population.

In a cross-sectional, population-based study we measured casual, seated blood pressure with a random-zero sphygmomanometer and 1,25-dihydroxyvitamin D (1,25-[OH]2D) with a protein-binding assay in 373 women aged 20-80 y. 1,25-(OH)2D, an active metabolite that regulates serum calcium, was associated significantly and positively with systolic blood pressure (p = 0.020) and diastolic blood pressure (p = 0.003) after adjustment for age, Quetelet's index (a measure of obesity), and current thiazide use. A model including age, Quetelet's index, current thiazide use, and 1,25-(OH)2D explained 37% of the variability in systolic blood pressure observations, of which 7% of variability was explained by 1,25-(OH)2D. In this geographically defined population of women, the variability of blood-pressure measurements attributable to 1,25-(OH)2D was of the same order of magnitude as that attributable to Quetelet's index.

Adolescent↗

PubMed1984

Effects of smoking on the development of female reproductive cancers.

The effect of smoking on the development of breast, endometrial, and ovarian cancers is evaluated among cases identified between November 1980 and July 1982 in the Iowa Surveillance, Epidemiology, and End Results Cancer Registry. Population-based, age-frequency matched controls were also evaluated, adjusting for potential confounders: Age, age of menarche, age of menopause, duration of menses, female family reproductive cancer history, obesity, parity, infertility, and lifetime steroid hormone use. Logistic regression analyses of total pack-years of cigarette exposure indicate that smoking is not significantly related to the development of breast cancer [relative risk (RR) = .99; confidence interval (CI) = .97, 1.02] or ovarian cancer (RR = 1.00; CI = 1.00, 1.00). Among women with endometrial cancer, the risk for those who smoke is increased among premenopausal women (RR = 1.27; CI = .65, 2.59) and decreased among postmenopausal women (RR = .41; CI = .16, 1.04).

Adipose Tissue↗