Biomedical subjects

Richard L Prince

Publications and source records attributed to Richard L Prince.

8 recordsLinked to original sources

PubMed2026

Association of high-sensitivity cardiac troponin I levels below the sex-specific 99th percentile with late-life dementia: the Perth Longitudinal Study of Ageing Women.

BACKGROUND: Elevated high-sensitivity cardiac troponin (hs-cTn) levels are linked with cardiovascular disease and cognitive impairment, both of which are strong risk factors for late-life dementia (LLD). This study examined the association between hs-cTnI levels below the sex-specific 99th percentile for myocardial injury and the incidence of LLD in older women. METHODS: 986 community-dwelling women aged ≥70 years without prior LLD and with hs-cTnI <15.6 ng/L (stratified into quartiles) were included from the Perth Longitudinal Study of Ageing Women. The primary outcome was incident LLD events, including LLD hospitalisation or death, over 14.5 years obtained from linked health records. Associations between hs-cTnI and LLD outcomes were explored using multivariable-adjusted Cox models, as part of restricted cubic splines. RESULTS: At baseline, participants' mean (±SD) age was 75.2±2.7 years. Over 14.5 years of follow-up, LLD events (n=174, 17.7%), hospitalisations (n=155, 15.7%) and deaths (n=68, 6.9%) were recorded. Compared with those in the lowest quartile (Q1, median 3.1 ng/L), women in the highest quartile of hs-cTnI (Q4, median 7.3 ng/L) had a greater risk of developing LLD-related events (adjusted HR: 1.88, 95% CI: 1.22 to 2.91), hospitalisation (adjusted HR: 1.65, 95% CI: 1.04 to 2.64) and death (adjusted HR: 2.27, 95% CI: 1.13 to 4.59), after adjusting for established cardiovascular and dementia risk factors, including apolipoprotein E (APOE) genotype. CONCLUSION: Among older women, hs-cTnI levels below the sex-specific 99th percentile for myocardial injury were associated with an increased risk of LLD events over 14.5 years. These findings suggest that hs-cTnI may identify older women at higher risk of LLD, capturing both cardiovascular and brain health vulnerability in older age. TRIAL REGISTRATION NUMBER: ACTRN12617000640303.

Humans↗

PubMed2022

Abdominal aortic calcification on lateral spine images captured during bone density testing and late-life dementia risk in older women: A prospective cohort study.

BACKGROUND: Dementia after the age of 80 years (late-life) is increasingly common due to vascular and non-vascular risk factors. Identifying individuals at higher risk of late-life dementia remains a global priority. METHODS: In prospective study of 958 ambulant community-dwelling older women (≥70 years), lateral spine images (LSI) captured in 1998 (baseline) from a bone density machine were used to assess abdominal aortic calcification (AAC). AAC was classified into established categories (low, moderate and extensive). Cardiovascular risk factors and apolipoprotein E (APOE) genotyping were evaluated. Incident 14.5-year late-life dementia was identified from linked hospital and mortality records. FINDINGS: At baseline women were 75.0 ± 2.6 years, 44.7% had low AAC, 36.4% had moderate AAC and 18.9% had extensive AAC. Over 14.5- years, 150 (15.7%) women had a late-life dementia hospitalisation (n = 132) and/or death (n = 58). Compared to those with low AAC, women with moderate and extensive AAC were more likely to suffer late-life dementia hospitalisations (9.3%, 15.5%, 18.3%, respectively) and deaths (2.8%, 8.3%, 9.4%, respectively). After adjustment for cardiovascular risk factors and APOE, women with moderate and extensive AAC had twice the relative hazards of late-life dementia (moderate, aHR 2.03 95%CI 1.38-2.97; extensive, aHR 2.10 95%CI 1.33-3.32), compared to women with low AAC. INTERPRETATION: In community-dwelling older women, those with more advanced AAC had higher risk of late-life dementia, independent of cardiovascular risk factors and APOE genotype. Given the widespread use of bone density testing, simultaneously capturing AAC information may be a novel, non-invasive, scalable approach to identify older women at risk of late-life dementia. FUNDING: Kidney Health Australia, Healthway Health Promotion Foundation of Western Australia, Sir Charles Gairdner Hospital Research Advisory Committee Grant, National Health and Medical Research Council of Australia.

AAC, abdominal aortic calcification↗

PubMed2003

Tea intake is inversely related to blood pressure in older women.

Tea is rich in polyphenols, which have activities consistent with blood pressure-lowering potential. The effects of long-term regular ingestion of tea on blood pressure remain uncertain. We investigated the relationships of tea intake and a biomarker of exposure to tea-derived polyphenols (4-O-methylgallic acid) with blood pressure in a cross-sectional study of 218 women > 70 y old. Clinic blood pressures were measured and tea intake was assessed using a 24-h dietary recall; 4-O-methylgallic acid was measured for the same period in a 24-h urine sample. Mean (95% CI) daily tea intake was 525 (475, 600) mL. Mean systolic and diastolic blood pressures were 138.1 (135.6, 140.6) and 73.5 (72.1, 74.9) mm Hg. Higher tea intake and higher 4-O-methylgallic acid excretion were associated with significantly lower systolic (P = 0.002 and P = 0.040, respectively) and diastolic (P = 0.027 and P < 0.001, respectively) blood pressures. A 250 mL/d (1 cup) increase in tea intake was associated with a 2.2 (0.8, 3.6) mm Hg lower systolic blood pressure and a 0.9 (0.1, 1.7) mm Hg lower diastolic blood pressure. The observed associations for both tea intake and 4-O-methylgallic acid are consistent with the hypothesis that long-term regular ingestion of tea may have a favorable effect on blood pressure in older women.

Aged↗

PubMed2003

Effects of a herbal extract on the bone density, strength and markers of bone turnover of mature ovariectomized rats.

For many decades, the Chinese have been using herbal medications to treat bone diseases. To examine effects of an extract of ten medicinal herbs on estrogen deficiency bone loss, ten-month-old female rats were randomly divided into three groups: ovariectomized (OVX), OVX treated with herbs (OVX-M) 4 ml/day by gavage, and OVX treated with estrogen (OVX-E) 10 mg subcutaneously (s.c.) twice per week. The bone mineral density (BMD) of the left femur (fBMD), spine (sBMD) and global body (gBMD) were measured at baseline and at 4, 8 and 12 weeks using a Hologic QDR 2000 dual-energy X-ray densitometer. Tibial strength was tested using the Instron Model 5566 electro-mechanical testing machine. The urinary pyridinoline creatinine ratio (Pyd/Cr), deoxypyridinoline creatinine ratio (Dpd/Cr), plasma alkaline phosphatase (ALP), calcium (CA), phosphorus (P) and albumin (ALB) were also determined. Uterine weight was determined at 12 weeks. The results showed that percent changes of fBMD in the OVX (n = 9), OVX-E (n = 8) and OVX-M (n = 8) rats at the 12-week time point were -11.8 +/- 4.6(c), 1.8 +/- 3.1(a), -7.6 +/- 1.9(abc) (p < 0.05-0.001, a: vs. OVX, b: vs. OVX-E, c: vs. baseline); sBMD were -10.7 +/- 4.6(c), -0.3 +/- 5.5(a), -5.9 +/- 3.5(abc); and gBMD were -4.8 +/- 2.3(c), 0.1 +/- 2.4(a), -2.7 +/- 2.6(abc), respectively. Further, the tibia maximum breaking stress and flexural modulus of elasticity in OVX-M rats (295 +/- 33(a), 18,194 +/- 3,264(a)) were significantly higher (p < 0.005-0.001) than that in OVX rats (189 +/- 83, 10,309 +/- 4,930), and similar to OVX-E rats (298 +/- 35(a), 18,766 +/- 2,620(a)). Additionally, the herbal extract reduced the urinary Pyd/Cr, Dpd/Cr and plasma ALP increment followed OVX and was not associated with a rise in uterine weight. In conclusion, the herbal extract demonstrated a therapeutic effect to inhibit bone resorption and to reduce estrogen-dependent bone loss without uterine stimulation. It may have potential as a new approach in treating and preventing postmenopausal osteoporosis (PMOP).

Alkaline Phosphatase↗

PubMed2003

Impact of the analysis of a bone density reference range on determination of the T-score.

There are uncertainties concerning the optimal threshold value of bone mineral density (BMD) for the diagnosis of osteoporosis using dual-energy X-ray absorptiometry (DXA). The most widely accepted clinical criteria are based on T- and Z-scores, derived statistically from an age-dependent BMD reference range that includes healthy young adults. This study has compared different analyses of BMD data of healthy, nonfractured, adult white females aged 18-90 years, consisting of 953 studied with DXA in the L1-L4 spine and 1018 measured at the hip. Four regression curves were applied to each reference data set; mean peak BMD (PBMD(R)) and the age-independent standard deviation (SD(R)) were calculated. These data, plus derived T-score thresholds, were compared with equivalent values (PBMD(YN), SD(YN)) determined from BMDs of a subgroup of young normals. Choice of regression curve caused a variation of 0.044 g/cm(2) in spinal PBMD(R) and 0.015-0.022 g/cm(2) in the hip. The variation in calculated SD(R) between the regressions was minimal (maximum variation, 0.03 SD unit in the spine). A split-linear model was chosen as the best overall fit for both the spine and the hip on the basis of goodness-of-fit and biological plausibility. PBMD(R) and PBMD(YN) varied by less than 1% at the spine or hip. Although the difference between SD(R) and SD(YN) was < or =7% for the hip sites, SD(R) was 0.022 g/cm(2) > SD(YN) for the spine (17% difference). At each hip site, BMD T-score thresholds, derived from regression analysis of the entire reference range (T(R)) or from young normals only (T(YN)), were not significantly different; however, equivalent spinal values differed by 0.062 g/cm(2) for T = -2.5. The percentage of the Australian female population (AFP) aged 50 yr or older and classified as osteoporotic, using population census data and the split-line-based T-score threshold of T(R) = -2.5, was 23% for spinal BMD and 17% for the total hip. For T(YN) = -2.5, the values were 36% (spine) and 17% (total hip). The hip BMDs of this study were greater than those of NHANES III in the third, seventh and eighth decades by as much as 0.6 SD. This produced a difference of 0.049-0.077 g/cm(2) for T(YN) = -2.5 between the two reference ranges.

Absorptiometry, Photon↗

PubMed2002

EBM in action.

Explore the source record for details and available documents.

Attitude of Health Personnel↗

PubMed2002

Recreational physical activity levels in healthy older women: the importance of fear of falling.

OBJECTIVES: To examine whether fear of falling is a probable cause of reduced recreational physical activity levels in healthy older women. DESIGN: Cross-sectional analysis of baseline data from a longitudinal study. PARTICIPANTS: One thousand five hundred older, ambulatory women (aged 70-85), selected at random from the electoral roll. MEASUREMENTS: Self-reported recreational physical activity levels and fear of falling, demographic variables, anthropometric variables and measures of disability, and physical and cognitive function. RESULTS: The study subjects had low levels of physical and cognitive impairments; 24.1% of the group was obese (body mass index> 30). Twenty-six percent of the women did not participate in recreational physical activity; 39% participated in sufficient activity to gain probable health benefits. Although the women who did not participate in recreational activities were most likely to report fear of falling (45.2%), it was common in the group as a whole (33.9%), including the most active women (27.0%). Independent risk factors for nonparticipation in physical activity were fear of falling (odds ratio (OR)=0.70, 95% confidence interval (CI)=0.54-0.90, P=.006), obesity (OR=0.50, 95% CI=0.38-0.66, P=.001), and slower times on the timed up-and-go test (OR=0.88, 95% CI=0.84-0.92, P=.001). Fear of falling was also independently associated with lower recreational physical activity levels in women who were active (beta=-0.09, P=.003). Subgroup analysis suggested that fear of falls affected activity levels at a predisability stage in women with mildly impaired mobility. CONCLUSIONS: Fear of falling is common in healthy, high-functioning older women and is independently associated with reduced levels of participation in recreational physical activity. Fear of falling is an important psychological barrier that may need to be overcome in programs attempting to improve activity levels in older women.

Accidental Falls↗

PubMed2002

Effects of vitamin D metabolites on intestinal calcium absorption and bone turnover in elderly women.

BACKGROUND: The relative importance of vitamin D metabolites in the regulation of gut calcium absorption has not been well studied in elderly women living in an environment with abundant sunlight. OBJECTIVE: The objective was to examine the determinants of active gut calcium absorption ( +/- SD: 42 +/- 11%) after an overnight fast with the use of a low (10 mg) calcium load. DESIGN: One hundred twenty elderly women aged 74.7 +/- 2.6 y underwent an active calcium absorption test with a radioactive calcium tracer, dietary analysis, and measurement of markers of bone turnover and calcium metabolism. RESULTS: The mean serum 25-hydroxyvitamin D [25(OH)D] concentration at the time of the calcium absorption test was 68 +/- 29 nmol/L. Gut calcium absorption was correlated with 25(OH)D but not 1,25-dihydroxyvitamin D (calcitriol), the free calcitriol index, or dietary calcium intake. After adjustment for age, calcitriol concentration, and dietary calcium intake, the significant determinant of fractional calcium absorption was the 25(OH)D concentration (r = 0.34, P = 0.001). When body weight was included in the regression, both 25(OH)D (beta = 1.20 x 10(-3)) and calcitriol (beta = 1.00 x 10(-3)) were significantly correlated with calcium absorption. Despite the strong relation between 25(OH)D and gut calcium absorption, there was no relation with other aspects of bone turnover or calcium metabolism. CONCLUSION: These data suggest that at low calcium loads, 25(OH)D is a more important determinant of gut calcium absorption than is calcitriol in elderly women exposed to abundant sunlight, but that this relation has little effect on overall calcium metabolism.

25-Hydroxyvitamin D 2↗