Biomedical subjects

Katie Stone

Publications and source records attributed to Katie Stone.

8 recordsLinked to original sources

PubMed2005

Sex hormones, risk factors, and risk of estrogen receptor-positive breast cancer in older women: a long-term prospective study.

OBJECTIVE: Antiestrogens reduce the risk of estrogen receptor-positive (ER+) but not ER-negative (ER-) breast cancer. Women at high risk of ER+ cancer would be the most likely to benefit from these treatments, but the best approach to predicting ER+ cancer is uncertain. METHODS: We prospectively assessed putative risk factors for breast cancer and archived serum at -190 degrees C from a community-based cohort of 7,676 women ages > or =65 years who had no history of breast cancer. Follow-up for breast cancer over 10.5 years was 99% complete. Using a case-cohort design, we measured baseline levels of estradiol and testosterone in 196 cases of invasive ER+ cancer and 378 randomly selected controls. RESULTS: Women whose testosterone level in highest two quintiles had a 4-fold increased risk of ER+ breast cancer (P < 0.0001). High estradiol concentration also indicated an increased risk but was not a significant predictor after adjustment for testosterone. Women with >16 years of education had a 2.1 times increased risk (P = 0.03) of ER+ cancer, but no other risk factors were significantly related to an increased risk of ER+ cancer. Women with a family history of breast cancer had a 2.9-fold increased risk of ER- cancer (P = 0.002) but no increased risk of ER+ cancer (relative hazard = 1.2, 0.8-1.8). CONCLUSIONS: High serum testosterone and advanced education predicted ER+ breast cancer. If confirmed, high testosterone level may be more accurate than family history of breast cancer and other conventional risk factors for identifying older women who are most likely to benefit from antiestrogen chemoprevention.

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PubMed2004

Hearing sensitivity and the risk of incident falls and fracture in older women: the study of osteoporotic fractures.

PURPOSE: To determine if age-related hearing loss may be related to bone health. Decreased vestibular function has been associated with hearing loss. We hypothesized that hearing loss would be related to an increased risk of falling and osteoporotic fracture in 6480 women aged 65 years or older enrolled in the Study of Osteoporotic Fractures. We further hypothesized that decreased bone mineral density would be associated with hearing loss. METHODS: Hearing sensitivity was ascertained via screening audiometry, and was classified as normal, mild loss, or significant loss. Incident non-spine fractures and falls were ascertained every 4 months for an average 6.7 years and 3 years, respectively. RESULTS: The age-adjusted annual fall rate did not differ significantly by hearing category, nor did the risk of incident fracture. Adjustment for confounding factors had no effect on our results. Age- and BMI-adjusted mean calcaneal bone mineral density (g/cm2) was 0.380 in the normal hearing group, 0.375 in the mild loss group, and 0.371 in the significant loss group (p = 0.02). There were no significant differences in total hip bone mineral density across hearing categories. CONCLUSIONS: Our results do not support the hypothesis that hearing loss is a risk factor for fracture or falls [corrected]

Accidental Falls↗

PubMed2004

Higher risk of multiple falls among elderly women who lose visual acuity.

OBJECTIVE: To determine the association between changes in visual acuity (VA) and frequent falls in older women. DESIGN: Prospective cohort study. PARTICIPANTS: Two thousand two elderly community-residing women participating in the Study of Osteoporotic Fractures with measurements of VA at baseline and a follow-up examination 4 to 6 years later (mean of 5.6 years). METHODS: Binocular VA with habitual correction was measured under standard illumination using Bailey-Lovie charts at baseline and fourth examinations. Change in VA was stratified into 5 categories: no change or VA gain, loss of 1 to 5 letters, loss of 6 to 10 letters, loss of 11 to 15 letters, and loss of >15 letters. A separate analysis considered decline in VA as the loss of >or=10 letters (>or=2 lines) on the Bailey-Lovie acuity measure between baseline and follow-up examinations. MAIN OUTCOME MEASURES: Data on falls were obtained from postcards sent every 4 months after the follow-up examination. Frequent falling was defined as >or=2 falls during a 1-year period after the follow-up examination. RESULTS: Compared with women with stable or improved VA, women with declining acuity had significantly greater odds of experiencing frequent falling during the subsequent year. Odds ratios after adjustment for baseline acuity and other confounders were 2.08 (95% confidence interval [CI]: 1.39-3.12) for loss of 1 to 5 letters, 1.85 (95% CI: 1.16-2.95) for loss of 6 to 10 letters, 2.51 (95% CI: 1.39-4.52) for loss of 11 to 15 letters, and 2.08 (95% CI: 1.01-4.30) for loss of >15 letters. In the analysis of visual decline defined as a loss of >or=10 letters, heightened risk of frequent falling was evident in each of 2 subgroups defined by splitting the sample on baseline VA, with borderline significant evidence of a more pronounced effect in those women with baseline VA of 20/40 or worse (P value for interaction, 0.083). CONCLUSIONS: Loss of vision among elderly women increases the risk of frequent falls. Prevention or correction of visual loss may help reduce the number of future falls.

Accidental Falls↗

PubMed2003

Relationship of changes in physical activity and mortality among older women.

CONTEXT: Physical activity has been related to reduced mortality, but it is not clear whether changes in physical activity affect mortality among older women. OBJECTIVE: To examine the relationship of changes in physical activity and mortality among older women. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study conducted at 4 US research centers (Baltimore, Md; Portland, Ore; Minneapolis, Minn; and Monongahela Valley, Pa) among 9518 community-dwelling white women aged 65 years or older who were assessed at baseline (1986-1988), 7553 of whom were reassessed at a follow-up visit (1992-1994; median, 5.7 years later). MAIN OUTCOME MEASURES: Walking and other physical activities at baseline and follow-up; vital status, with cause of death confirmed by death certificates/discharge summaries, tracked for up to 12.5 years after baseline (up to 6.7 years after the follow-up visit). RESULTS: Compared with continually sedentary women, those who increased physical activity levels between baseline and follow-up had lower mortality from all causes (hazard rate ratio [HRR], 0.52; 95% confidence interval [CI], 0.40-0.69), cardiovascular disease (HRR, 0.64; 95% CI, 0.42-0.97), and cancer (HRR, 0.49; 95% CI, 0.29-0.84), independent of age, smoking, body mass index, comorbid conditions, and baseline physical activity level. Associations between changes in physical activity and reduced mortality were similar in women with and without chronic diseases but tended to be weaker among women aged at least 75 years and among those with poor health status. Women who were physically active at both visits also had lower all-cause mortality (HRR, 0.68; 95% CI, 0.56-0.82) and cardiovascular mortality (HRR, 0.62; 95% CI, 0.44-0.88) than sedentary women. CONCLUSION: Increasing and maintaining physical activity levels could lengthen life for older women but appears to provide less benefit for women aged at least 75 years and those with poor health status.

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PubMed2003

Bone loss predicts subsequent cognitive decline in older women: the study of osteoporotic fractures.

OBJECTIVES: To determine whether the rate of bone loss predicts subsequent cognitive decline independently of baseline bone mass and whether apolipoprotein E (ApoE) genotype explains the association. DESIGN: A prospective cohort study. SETTING: Clinical centers in Baltimore, Maryland; Minneapolis, Minnesota; Pittsburgh, Pennsylvania; and Portland, Oregon. PARTICIPANTS: Four thousand four hundred sixty-two women aged 70 and older (mean = 75.8) participating in the Study of Osteoporotic Fractures. MEASUREMENTS: Total hipbone mineral density (BMD) was measured 2 and 6 years after enrollment (mean follow-up = 3.5 years), and expressed as annualized percentage rate of bone change. A modified Mini-Mental State Examination (mMMSE) was administered at 6 and 10 years (mean follow-up = 4.5 years) and defined cognitive decline as a decline of three or more points on repeat mMMSE score. ApoE genotype information was available on 883 women. RESULTS: Cognitive decline occurred in 12% of the women with the least bone loss (by quartile), 14% in the second, 16% in the third, and 20% in those with the greatest bone loss. After adjustment for age, education, stroke, functional status, estrogen use, body mass index, and smoking, the results were similar. Those who lost the most BMD were almost 40% more likely than women in the lowest quartile to develop cognitive decline in the multivariate model (odds ratio (OR) = 1.4, 95% confidence interval (CI) = 1.1-1.8). A similar association between hipbone loss and cognitive decline was observed in the multivariate model further adjusting for ApoE e4 (OR = 1.5, 95% CI = 0.8-2.7). CONCLUSIONS: Women with more rapid hipbone loss were more likely to develop cognitive decline than those who had lower rate of loss (or who gained bone mass). Differences in functional status, estrogen use, and ApoE did not explain this association. Further investigation is needed to determine the mechanisms that link osteoporosis and cognitive decline.

Absorptiometry, Photon↗

PubMed2002

Estrogen receptor 1 polymorphisms and risk of cognitive impairment in older women.

BACKGROUND: Several genes associated with sporadic Alzheimer's disease have been identified; however, approximately 50% of genetic factors remain unidentified. We investigated whether estrogen receptor 1 (ESR1) polymorphisms are associated with risk of developing cognitive impairment in older women. METHODS: A total of 2625 women > or = 65 years of age completed a modified Mini-Mental Status Exam (mMMSE) at baseline and at 6-8 years of follow-up. We defined cognitive impairment as a mMMSE decline of > or = 3 points, follow-up score < or = 20, or a history of physician-diagnosed dementia. The ESR1 polymorphisms, PvuII (P or p) and XbaI (X or x), were coded so that the capital letter signifies the absence of the restriction site. RESULTS: Women with a p allele had a greater age, education, and baseline-score adjusted decline in mMMSE (for PP, Pp, and pp, respectively:.6 +/-.1,.8 +/-.1, and.9 +/-.1 points, p for trend =.01); women with at least one x allele also had greater score decline (XX, Xx, and xx:.7 +/-.1,.7 +/-.1, and.9 +/-.1 points, p for trend =.02). Six percent (n = 166) of the women developed cognitive impairment. Compared to those who did not develop impairment, more women who developed cognitive impairment had a p allele (62% vs. 56%, p =.03; adjusted odds ration (OR) = 1.33; 95% confidence interval [CI], 1.03-1.72) or an x allele (70% vs. 64%, p =.03; adjusted OR = 1.38; 95% CI, 1.06-1.81). There was no interaction with current estrogen use, or with serum estradiol level and ESR1 polymorphisms (p >.10). CONCLUSIONS: Estrogen receptor 1 polymorphisms are associated with risk of developing cognitive impairment. More research is needed to determine the mechanism whereby ESR1 polymorphisms or linked genes influence cognitive function in older women.

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PubMed2002

Distal radius fractures in older women: a 10-year follow-up study of descriptive characteristics and risk factors. The study of osteoporotic fractures.

OBJECTIVES: To determine the incidence of distal radius fractures and the characteristics of those fractures and to identify the key risk factors. DESIGN: Prospective cohort study, mean follow-up of 9.8 years. SETTING: Four clinical centers, one each in Baltimore, Maryland; Minneapolis, Minnesota; Pittsburgh, Pennsylvania; and Portland, Oregon. PARTICIPANTS: Nine thousand seven hundred four white women aged 65 and older, enrolled in the multicenter Study of Osteoporotic Fractures. METHODS: Five hundred twenty-seven distal radius fractures were confirmed by physician review of radiology reports; characteristics of the fractures were noted. Information was also collected on lifestyle, demographics, bone mineral density (BMD), and clinical and performance measures. RESULTS: The overall incidence of fracture was 7.3/1,000 person-years. Twenty-seven percent of the fractures were intra-articular; 73% were extra-articular. The independent predictors of fracture were decreased BMD (per 0.1 g/cm(2)) at the distal radius ( relative risk ( RR)=1.8, 95% confidence interval ( CI)=1.6-2.1), a history of recurrent falls ( RR=1.6, 95% CI=1.2-2.0), and having had a previous fracture since age 50 ( RR=1.3, 95% CI=1.1-1.6). Current use of oral estrogen was protective ( RR=0.6, 95% CI=0.4-0.8). For women aged 75 and older, poor cognitive status was also a predictor of wrist fracture. Intra-articular fractures occurred more than twice as frequently in women with diabetes mellitus. CONCLUSIONS: This is the first large long-term comprehensive study of distal radius fractures in older people. The results indicate that factors predictive of distal radius fractures can easily be assessed in routine clinical practice and can identify women at high risk for fracture. Selected preventive strategies could be designed to reduce the incidence of these fractures.

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PubMedDate not supplied

Classification algorithms for hip fracture prediction based on recursive partitioning methods.

This article presents 2 modifications to the classification and regression tree. The authors improved the robustness of a split in the test sample approach and developed a cost-saving classification algorithm by selecting noninferior to the optimum splits from variables with lower cost or being used in parent splits. The new algorithm was illustrated by 43 predictive variables for 5-year hip fracture previously documented in the Study of Osteoporotic Fractures. The authors generated the robust optimum classification rule without consideration of classification variable costs and then generated an alternative cost-saving rule with equivalent diagnostic utility. A 6-fold cross-validation study proved that the cost-saving alternative classification is statistically noninferior to the optimal one. Their modified classification and regression tree algorithm can be useful in clinical applications. A dual X-ray absorptiometry hip scan and information from clinical examinations can identify subjects with elevated 5-year hip fracture risk without loss of efficiency to more costly and complicated algorithms.

Absorptiometry, Photon↗