Biomedical subjects

Elizabeth Barrett-Connor

Publications and source records attributed to Elizabeth Barrett-Connor.

At least 37 records · Page 2Linked to original sources

PubMed2006

Ghrelin and bone: is there an association in older adults?: the Rancho Bernardo study.

UNLABELLED: Laboratory studies suggest that ghrelin is involved in bone metabolism, but studies of ghrelin and bone in humans are limited. We studied sex-specific associations of ghrelin with BMD, NTX, and bone loss. Ghrelin was not associated with BMD or bone loss in either sex. There was a significant inverse association with NTX in men but not in women. INTRODUCTION: Ghrelin is a gastric hormone recently shown to be associated with bone metabolism in animal and in vitro studies. Studies in humans are limited. We investigated the association of ghrelin with BMD, the bone resorption marker N-telopeptide (NTX), and bone loss in older men and women. MATERIALS AND METHODS: Participants were 977 community-dwelling men and non-estrogen-using postmenopausal women, 50-91 years of age. Plasma ghrelin was measured by radioimmunoassay from blood obtained between 1984 and 1987. Between 1988 and 1991, BMD was measured at the midshaft radius by single photon absorptiometry and at the femoral neck, total hip, and lumbar spine by DXA. Axial BMD measurements were repeated an average of 4 years later in 544 participants. Bone turnover was assessed by NTX in urine obtained at the same time as the initial BMD. Multiple regression analyses were used to test sex-specific associations of ghrelin with BMD, NTX, and bone loss in both sexes. RESULTS: No significant ghrelin-BMD or ghrelin-bone loss associations were observed in either sex, after adjusting for age and body mass index (BMI). Ghrelin was inversely associated with NTX in men and positively associated with NTX in women, independent of age. After adjusting for both age and BMI, this association reached statistical significance in men and was weakened in women. CONCLUSIONS: Ghrelin may be associated with bone turnover, but there is no evidence for an association with BMD or short-term change in BMD in older adults.

Absorptiometry, Photon↗

PubMed2006

Impact of recent fracture on health-related quality of life in postmenopausal women.

UNLABELLED: The effect of fractures other than hip and spine on HRQoL in younger and older women has not been extensively studied. In a cohort of 86,128 postmenopausal women, we found the impact of recent osteoporosis-related fractures on HRQoL to be similar between women < 65 compared with those > or = 65 years of age. The impact of spine, hip, or rib fractures was greater than that of wrist fractures in both age groups. INTRODUCTION: Health-related quality of life (HRQoL) after vertebral and hip fractures has been well studied. Less is known about HRQoL after fractures at other sites. We studied the effect of recent clinical fractures on HRQoL, using Short Form-12 (SF-12). MATERIALS AND METHODS: This study included 86,128 postmenopausal participants in the National Osteoporosis Risk Assessment (NORA) who responded to two follow-up surveys during a 2-year interval. At each survey, they completed the SF-12 HRQoL questionnaire and reported new fractures of the hip, spine, wrist, and rib. The effect of recent fracture on HRQoL was assessed by comparing Physical Component Score (PCS) and Mental Component Score (MCS) means for women with and without new fractures at the second survey. Analyses were by fracture type and by age group (50-64 and 65-99) and were adjusted for PCS and MCS at the first survey. RESULTS: New fractures (320 hip, 445 vertebral, 657 rib, 835 wrist) occurring during the interval between the first and second follow-up surveys were reported by 2257 women. The PCS was poorer in both older and younger women who had fractured the hip, spine, or rib (p < or = 0.001). Wrist fractures had an impact on PCS in women < or = 65 years of age (p < 0.001), but not older women (p > 0.10). These differences in PCS by fracture status were similar to those reported for other chronic diseases such as asthma, chronic obstructive pulmonary disease (COPD), and osteoarthritis. MCS was less consistently changed by fracture status, but younger and older women with vertebral fracture (p < 0.004), older women with hip fracture (p < 0.004), and younger women with rib fracture (p < 0.004) had poorer MCS compared with those who did not fracture within their age cohort. CONCLUSIONS: Recent osteoporosis-related fractures have significant impact on HRQoL as measured by SF-12. The impact of recent fracture on HRQoL was similar for older and younger postmenopausal women. Fracture prevention and postfracture interventions that target the subsequent symptoms are needed for postmenopausal women of any age.

Age Distribution↗

PubMed2006

Cardiovascular death and the metabolic syndrome: role of adiposity-signaling hormones and inflammatory markers.

OBJECTIVE: Levels of adiposity-signaling hormones and inflammatory markers are less favorable in individuals with the metabolic syndrome; their role in the association between the metabolic syndrome and cardiovascular mortality remains unclear. RESEARCH DESIGN AND METHODS: We conducted a prospective study of 977 men and 1,141 women aged 40-94 years in 1984-1987, followed for mortality for a maximum of 20 years. Adiponectin, leptin, ghrelin, interleukin-6 (IL-6), C-reactive protein (CRP), and Adult Treatment Panel III-defined metabolic syndrome components were measured in fasting blood samples obtained in 1984-1987. Cox-proportional hazards models were used in survival analyses. RESULTS: The age- and sex-adjusted hazard ratio (HR) (95% CI) for coronary heart disease (CHD) mortality associated with the metabolic syndrome was 1.65 (1.25-2.18) (P < 0.001); this association did not differ significantly by sex, age, or diabetic status (P > 0.2 for each interaction). The association between the metabolic syndrome and CHD mortality was not materially changed after adjustment for adiponectin, leptin, and ghrelin; it was attenuated by 25% after adjustment for IL-6 and 35% after adjustment for CRP. CHD mortality increased linearly with greater levels of IL-6 and CRP (P(trend) < 0.001 for each); the age- and sex-adjusted HRs comparing highest versus lowest quarter were 3.0 (1.87-4.89) for IL-6 and 2.1 (1.41-3.21) for CRP. IL-6, but not CRP, remained a significant predictor of CHD mortality in models including both inflammatory markers and the metabolic syndrome. CONCLUSIONS: Adiposity-signaling hormones and inflammatory markers explain little to some of the association between the metabolic syndrome and CHD mortality. IL-6 levels predict CHD mortality independently of CRP.

Adult↗

PubMed2006

Does coffee consumption reduce the risk of type 2 diabetes in individuals with impaired glucose?

OBJECTIVE: The purpose of this study was to investigate the association between coffee intake and incident diabetes based on an oral glucose tolerance test (OGTT) and examine coffee habits in those with impaired glucose separately from those with normal glucose at baseline. RESEARCH DESIGN AND METHODS: In this prospective study, 910 adults aged >/=50 years without diabetes at baseline in 1984-1987 were followed to 1992-1996, an average of 8 years after assessment of coffee intake. Logistic regression models were adjusted for sex, age, physical activity, BMI, smoking, alcohol, hypertension, and baseline fasting plasma glucose. RESULTS: Past and current coffee drinkers had a reduced risk of incident diabetes (odds ratio 0.38 [95% CI 0.17-0.87] and 0.36 [0.19-0.68], respectively) compared with those who never drank coffee. The 317 participants with baseline impaired glucose who were past or current coffee drinkers were also at reduced risk for incident diabetes (0.31 [0.11-0.87] and 0.36 [0.16-0.83], respectively). CONCLUSIONS: This study confirms a striking protective effect of caffeinated coffee against incident diabetes and extends these findings to incident diabetes based on OGTT independent of multiple plausible confounders.

Aged↗

PubMed2006

Lifestyle intervention is associated with lower prevalence of urinary incontinence: the Diabetes Prevention Program.

OBJECTIVE: Diabetes is associated with increased urinary incontinence risk. Weight loss improves incontinence, but exercise may worsen this condition. We examined whether an intensive lifestyle intervention or metformin therapy among overweight pre-diabetic women was associated with a lower prevalence of incontinence. RESEARCH DESIGN AND METHODS: We analyzed data from the Diabetes Prevention Program, a randomized controlled trial in 27 U.S. centers. Of the 1,957 women included in this analysis, 660 (34%) were randomized to intensive lifestyle therapy, 636 (32%) to metformin, and 661 (34%) to placebo with standard lifestyle advice. The main outcome measure was incontinence symptoms by frequency and type by a validated questionnaire completed at the end-of-trial visit (mean 2.9 years). RESULTS: The prevalence of total (stress or urge) weekly incontinence was lower among women in the intensive lifestyle group (38.3%) than those randomized to metformin (48.1%) or placebo (45.7%). This difference was most apparent among women with stress incontinence (31.3% for intensive lifestyle group vs. 39.7% for metformin vs. 36.7% for placebo, P = 0.006). Changes in weight accounted for most of the protective effect of the intensive lifestyle intervention on stress incontinence. CONCLUSIONS: Less-frequent urinary incontinence may be a powerful motivator for women to choose lifestyle modification to prevent diabetes.

Adult↗

PubMed2006

Association of serum proinsulin with hormone replacement therapy in nondiabetic older women: the Rancho Bernardo Study.

OBJECTIVE: One putative benefit of hormone replacement therapy (HRT) is a reduced risk of diabetes or reduced fasting glucose level. We report here the association of HRT with proinsulin, insulin, and fasting and postchallenge glucose levels in older adults. RESEARCH DESIGN AND METHODS: Current HRT use was validated and cross-sectionally compared with diabetes-related variables in 785 women without diabetes by history or glucose tolerance test. RESULTS: Median age was 72 years (range 50-97); median value of fasting plasma glucose, postchallenge plasma glucose, and proinsulin was 5.08 mmol/l, 6.93 mmol/l, and 9.3 pmol/l, respectively. In age-adjusted comparisons, current HRT use was associated with significantly lower fasting plasma glucose and higher postchallenge plasma glucose compared with never/previous HRT use, as well as with lower LDL and higher HDL cholesterol and higher triglycerides. Fasting and postchallenge intact insulin did not differ by HRT group, but proinsulin was significantly lower in current HRT users than in previous and never HRT users. The significant association between proinsulin and HRT status persisted after adjustment for age, waist-to-hip ratio, pulse pressure, LDL-to-HDL cholesterol ratio, triglycerides, fasting and postchallenge glucose, and intact insulin. CONCLUSIONS: Reduced fasting and increased 2-h glucose replicate findings in a randomized clinical trial. The proinsulin effect has not been previously reported. Decreased fasting glucose and proinsulin levels in current HRT use suggest a potential antidiabetes effect of HRT. Increased postchallenge glucose in HRT, however, suggests insulin resistance and would be expected to increase the risk of heart disease.

Aged↗

PubMed2005

Sexual dysfunction and cardiac risk (the Second Princeton Consensus Conference).

Recent studies have highlighted the relation between erectile dysfunction (ED) and cardiovascular disease. In particular, the role of endothelial dysfunction and nitric oxide in ED and atherosclerotic disease has been elucidated. Given the large number of men receiving medical treatment for ED, concerns regarding the risk for sexual activity triggering acute cardiovascular events and potential risks of adverse or unanticipated drug interactions need to be addressed. A risk stratification algorithm was developed by the First Princeton Consensus Panel to evaluate the degree of cardiovascular risk associated with sexual activity for men with varying degrees of cardiovascular disease. Patients were assigned to 3 categories: low, intermediate (including those requiring further evaluation), and high risk. This consensus study from the Second Princeton Consensus Conference corroborates and clarifies the algorithm and emphasizes the importance of risk factor evaluation and management for all patients with ED. The panel reviewed recent safety and drug interaction data for 3 phosphodiesterase (PDE)-5 inhibitors (sildenafil, tadalafil, vardenafil), with emphasis on the safety of these agents in men with ED and concomitant cardiovascular disease. Increasing evidence supports the role of lifestyle intervention in ED, specifically weight loss and increased physical activity, particularly in patients with ED and concomitant cardiovascular disease. Special management recommendations for patients taking PDE-5 inhibitors who present at the emergency department and other emergency medical situations are described. Finally, further research on the role of PDE-5 inhibition in treating patients with other medical or cardiovascular disorders is recommended.

Cardiovascular Diseases↗

PubMed2005

Testosterone and estradiol among older men.

CONTEXT: Testosterone and estradiol levels decline with age in men. This change may affect multiple clinical outcomes, but there have been few reports of the distribution and correlates of testosterone and estradiol concentrations in elderly men. OBJECTIVE: The purpose of these studies was to assess sex steroid levels in a large cohort of older men. DESIGN: We conducted a cross-sectional cohort evaluation. SETTING: Community-dwelling men were studied at six academic medical centers in the United States. PARTICIPANTS: The Osteoporotic Fractures in Men Study is a prospective cohort of men aged at least 65 yr. In these studies, a randomly selected stratified subsample of 2623 participants was analyzed. MAIN OUTCOME MEASURES: We assessed levels of total and free testosterone and estradiol and SHBG. RESULTS: Age was inversely associated with free testosterone and free estradiol levels (P for trend = 0.001 for both). Notably, at any age, there was substantial variation in levels of each hormone. Free testosterone levels were lower in men with greater body mass index, lower SHBG, and poorer self-reported health status and in those of Asian race. Free estradiol concentrations were lower in men with lower body mass index and higher SHBG levels. Free estradiol and free testosterone were modestly correlated (r = 0.20; P < 0.001), but at any level of free testosterone, there was considerable variation in free estradiol levels. CONCLUSIONS: This is the largest cohort of older men in which sex steroid levels are available, and it demonstrates that testosterone and estradiol, and their free fractions, tend to decline with age even among older men. However, substantial variation is also present. The relationships between sex steroid levels and their consequences in aging are likely to be complex.

Aged↗

PubMed2005

Hyperkyphotic posture and risk of future osteoporotic fractures: the Rancho Bernardo study.

UNLABELLED: It is unknown whether kyphosis of the thoracic spine is an independent risk factor for future osteoporotic fractures. In 596 community-dwelling women, we found that with increasing kyphosis, there was a significant trend of increasing fracture risk that was independent of previous history of fractures or BMD. INTRODUCTION: It is unknown whether kyphosis of the thoracic spine is an independent risk factor for future osteoporotic fractures. MATERIALS AND METHODS: We conducted a prospective cohort study of 596 community-dwelling women, 47-92 years of age. Between 1988 and 1991, BMD of the hip and spine and kyphosis were measured. Kyphosis was measured by counting the number of 1.7-cm blocks necessary to place under the occiput so participants could lie flat without neck hyperextension. New fractures were reported over an average follow-up of 4 years. RESULTS: Using a cut-off of at least one block, 18% of the participants had hyperkyphotic posture (range, one to nine blocks). There were 107 women who reported at least one new fracture (hip, spine, wrist, clavicle, shoulder, arm, hand, rib, pelvis, leg, or ankle). In logistic regression analyses, older women with hyperkyphotic posture (defined as at least one block) had a 1.7-fold increased risk of having a future fracture independent of age, prior fracture, and spine or hip BMD (95% CI: 1.00-2.97; p = 0.049). There was a significant trend of increasing fracture risk with increasing number of blocks, with ORs ranging from 1.5 to 2.6 as the number of blocks increased from one to at least three blocks compared with those with zero blocks (trend p = 0.03; models adjusted for age, baseline fracture, spine or hip BMD). Stratification by baseline fracture status and controlling for other possible confounders or past year falls did not change the results. CONCLUSIONS: Whereas hyperkyphosis may often result from vertebral fractures, our study findings suggest that hyperkyphotic posture itself may be an important risk factor for future fractures, independent of low BMD or fracture history.

Aged↗

PubMed2005

Association between the ankle-brachial index and future coronary calcium (the Rancho Bernardo study).

This study investigated whether the ankle-brachial index (ABI) is associated with coronary artery calcium (CAC) in a cohort of men and women who were free of clinical coronary heart disease. CAC was assessed by electron beam computed tomography in 279 community-based subjects who also had ABI measurements 7 years previously. Patients' mean age was 65.8 years and 51.3% were women. Thirty-three patients (11.8%) had an ABI < 1.0, 11 (3.9%) had an ABI < 0.9, and 4 (1.4%) had an ABI < 0.8. Prevalences of any CAC were 70% for women and 95% for men. In men and women, there was a U-shaped relation between CAC and ABI category, with the lowest CAC score being in the interval from 1.0 to 1.09. On multivariable analysis, women whose ABI was < 1.0 had a 2.7-fold higher risk (p = 0.03) for increasing amounts of CAC. Men whose ABI was below this same cutpoint had a similar but nonsignificant increase in risk (odds ratio 2.1, p = 0.1). In conclusion, ABI was significantly associated with the presence and extent of future CAC measured 7 years later.

Adult↗

PubMed2005

Hyperglycemia and type 2 diabetes among Filipino women in the Philippines, Hawaii, and San Diego.

BACKGROUND: Diabetes risk increases as immigrant populations adopt western lifestyles. We compared the prevalence of fasting hyperglycemia among Filipino women aged 40-79 years in the Philippines, Hawaii, and San Diego. METHODS: Data were obtained from the (1) Philippine National Nutrition Survey (1998), (2) Native Hawaiian Health Research Project (1997-2001), and (3) University of California San Diego Filipino Women's Health Study (1995-1999). Fasting glucose after an 8h fast, blood pressure, and body mass index (BMI) were measured in all three regions; a 75 g oral glucose tolerance test was performed in San Diego and Hawaii. RESULTS: The proportion of Filipinas with BMI > or = 30 kg/m2 was higher in Hawaii (20%) compared to women in San Diego (9.3%) or the Philippines (5.2%, p<0.001). Fasting hyperglycemia prevalence (fasting plasma glucose > or = 126 mg/dl or fasting whole blood glucose > or = 110 mg/dl) did not differ among Filipinas in the Philippines (11.8%), San Diego (14.1%), and Hawaii (14.7%, p = 0.323). Type 2 diabetes prevalence was similar among Filipinas in San Diego (31.6%) and Hawaii (24.9%, p = 0.79). CONCLUSIONS: Despite regional differences in obesity, fasting hyperglycemia was similar among Filipinas in the Philippines, San Diego, and Hawaii and type 2 diabetes prevalence was similar among Filipinas in San Diego and Hawaii.

Adult↗

PubMed2005

Ghrelin, adiponectin, and leptin do not predict long-term changes in weight and body mass index in older adults: longitudinal analysis of the Rancho Bernardo cohort.

Ghrelin, leptin, and adiponectin are associated with body size in cross-sectional studies; it is unknown whether these hormones predict long-term changes in body size. Multilevel models were used to study associations between fasting serum hormones, measured in 698 men and 619 women (60-91 years) in samples collected at baseline (1984-1987), and changes in weight and body mass index, assessed repeatedly over a follow-up period of up to 18 years (median, 4.7 years). Baseline weight was -1.5 kg lower for a one-standard-deviation increment in ghrelin and -3.3 kg lower for a one-standard-deviation increment in adiponectin, similar in men and women. For leptin, baseline weight was 12.1 kg higher for a one-standard-deviation increment in men, compared with 5.7 kg in women (sex-interaction p < or = 0.0001). Ghrelin and adiponectin did not affect weight change; their associations with weight were constant over time, indicated by nonsignificant hormone-by-time interactions. The positive association between leptin and weight became slightly weaker over time. Results were similar when investigating repeated measures of body mass index. From this analysis of Rancho Bernardo Study data, the authors conclude that ghrelin, adiponectin, and leptin do not predict weight gain beyond reflecting the influence of attained body size on future changes in weight or body mass index.

Adiponectin↗

PubMed2005

Ghrelin and the metabolic syndrome in older adults.

CONTEXT: Ghrelin may be one of the pathophysiological mechanisms underlying risk factor clustering observed in the metabolic syndrome, but this has not been investigated. OBJECTIVE: The objective of this work was to study the association between ghrelin and the metabolic syndrome and identify social and behavioral determinants of ghrelin. DESIGN: This was a cross-sectional study. SETTING: The setting of this work was the Rancho Bernardo Study. PARTICIPANTS: Study subjects included 1513 men and women, aged 51-90 yr in 1984-1987. OUTCOMES: Total ghrelin, measured by RIA, and the metabolic syndrome, defined using Adult Treatment Panel III diagnostic criteria, were the outcome measures. RESULTS: Levels of ghrelin (mean +/- SD) did not differ between the 848 men (1451 +/- 532 pg/ml) and the 665 women (1459 +/- 672 pg/ml) or by age. Education, alcohol intake, and smoking history were each significantly and positively associated with ghrelin in a dose-related manner, independent of body mass index (BMI). Compared with participants with the lowest third of ghrelin levels, the age- and sex-adjusted odds of having the metabolic syndrome were 18% lower in the middle third and 53% lower in the highest third. This corresponds to a 21% decrease per SD increase in ghrelin (odds ratio, 0.79; 95% confidence interval, 0.69, 0.89; P < or = 0.001); this was attenuated to 13% (odds ratio, 0.87; 95% confidence interval, 0.75, 1.01; P = 0.07), after adjustment for BMI. Of the five metabolic syndrome components, only the association between ghrelin and high-density lipoprotein cholesterol was independent of BMI. A significant association independent of BMI was also observed between insulin and ghrelin. CONCLUSIONS: Ghrelin levels are influenced by lifestyle factors. The inverse association between endogenous ghrelin and the metabolic syndrome is largely explained by the strong ghrelin-BMI association.

Aged↗

PubMed2005

Serum insulin-like growth factor binding protein-1 levels and bone mineral density in older adults: the Rancho Bernardo Study.

Insulin-like growth factor-I (IGF-I) stimulates osteoblast function, inhibits collagen matrix degradation, and is positively associated with bone mineral density in most but not all studies. We previously reported that IGF-I was positively associated with BMD at the spine and hip in women but not men. Insulin-like growth factor binding protein-1 (IGFBP-1), a potent modulator of IGF-I, is expressed in normal osteoblasts and inhibits collagen gene expression in bone, but little is known about the relationship between IGFBP-1 and bone mineral density (BMD). We report a cross-sectional study of serum IGFBP-1 levels and BMD in 1,139 community-dwelling men and postmenopausal women (not using estrogen), aged 44-98. In both sexes, IGFBP-1 levels increased linearly with age (p<0.001) and decreased with body mass index (BMI) quartile (p<0.001). After adjusting for age and BMI, there was no significant association between IGFBP-1 and BMD at the hip or spine. IGF-I and IGFBP-1 were weakly and inversely associated with each other. These findings suggest that if there is an important role for IGFBP-1 in bone metabolism, it is mediated or confounded by weight. Studies are needed to further investigate the relationship between inhibitory components of IGF-1 and bone loss.

Absorptiometry, Photon↗

PubMed2005

Heart disease risk factors predict erectile dysfunction 25 years later (the Rancho Bernardo Study).

We prospectively examined common coronary artery disease (CAD) risk factors (age, smoking, hypertension, diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, and obesity) in 570 community-dwelling men, aged 30 to 69 years (mean age, 46 years) at baseline. After an average follow-up period of 25 years, incident erectile dysfunction (ED) was evaluated by the 5-item International Index of Erectile Function. Age, body mass index, and hypercholesterolemia were each significantly associated with an increased risk of ED. In all, 1 in 5 men had > or =3 risk factors and were at a 2.2-fold increased risk of ED. Improving CAD risk factors in midlife may decrease ED risk as well as CAD risk.

Adult↗

PubMed2005

Sexual dysfunction and cardiac risk (the Second Princeton Consensus Conference).

Age Distribution↗

PubMed2005

The effects of hormone therapy on the markers of inflammation and endothelial function and plasma matrix metalloproteinase-9 level in postmenopausal women: the postmenopausal estrogen progestin intervention (PEPI) trial.

OBJECTIVE: The objective of this study was to determine whether oral conjugated equine estrogen (CEE) alone or with one of the three progestin regimens causes changes in biomarkers predictive of adverse cardiovascular events: C-reactive protein (CRP), interleukin-6 (IL-6), intercellular adhesion molecule (ICAM) and matrix metalloproteinase-9 (MMP-9). METHODS AND RESULTS: The analysis included 271 postmenopausal women from the postmenopausal estrogen progestin intervention (PEPI) trial. Plasma levels of biomarkers were measured on frozen samples obtained at baseline, 1- and 3-year follow-up visits. Multivariable linear mixed effects models were used to estimate changes in CRP, IL-6, ICAM and MMP-9 levels from baseline to follow-up visits by treatment groups. Women assigned to CEE only or CEE plus a progestin had 121 and 150% 1-year increase in CRP levels, respectively. In contrast, these treatments caused no significant change in IL-6 levels. Women assigned to CEE with or without a progestin had a 6-8% decline in ICAM and a 26-33% decline in MMP-9. CONCLUSIONS: The linkage between CEE alone or with a progestin and increased cardiovascular events may be associated with a rise in CRP level, but not through the mechanisms of IL-6-mediated inflammation, endothelial dysfunction or increased MMP activity.

C-Reactive Protein↗

PubMed2005

Vitamin D, parathyroid hormone levels and bone mineral density in community-dwelling older women: the Rancho Bernardo Study.

Vitamin D (25(OH)D) increases the efficiency of intestinal calcium absorption. Low levels of serum calcium stimulate the secretion of parathyroid hormone (PTH), which maintains serum calcium levels at the expense of increased bone turnover, bone loss and increased risk of fractures. We studied the association between 25(OH)D and PTH levels, and their associations with bone mineral density (BMD), bone loss, and prevalence of hip fractures in 615 community-dwelling postmenopausal aged 50-97 years. Mean level of 25(OH)D and PTH were 102.0 nmol/l+/-35.0 nmol/l and 49.4 ng/l+/-23.2 nmol/l, respectively; 49% of women were current hormone therapy users. The overall prevalence of vitamin D insufficiency (25(OH)D<50 nmol/l) was 2%, and prevalence of high PTH levels (>65 ng/l) was 17.4%. In multiple linear regression analyses hip BMD was negatively and independently associated with PTH levels (p=0.04), and positively and independently associated with 25(OH)D levels (p=0.03). There were only 23 women (3.7%) who experienced a hip fracture. In age-adjusted analyses there were no significant differences of 25(OH)D and PTH levels by hip fracture status. Across the entire range of values, the overall correlation between 25(OH)D and PTH was moderate (r=-0.20). However, after the threshold vitamin D level of 120 nmol/l, all PTH values were below 65 ng/l. Further studies are necessary to identify the optimal vitamin D levels necessary to prevent secondary hyperparathyroidism.

Activities of Daily Living↗