Biomedical subjects

Saskia M F Pluijm

Publications and source records attributed to Saskia M F Pluijm.

16 recordsLinked to original sources

PubMed2006

Vitamin D status in relation to one-year risk of recurrent falling in older men and women.

BACKGROUND: Falls frequently occur in the elderly and are a major cause of morbidity and mortality. OBJECTIVE: The objective of the study was to prospectively investigate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and risk of recurrent falling in older men and women. DESIGN: This was a prospective cohort study. SETTING: An age- and sex-stratified random sample of the Dutch older population was determined. SUBJECTS: Subjects included 1231 men and women (aged 65 yr and older) participating in the Longitudinal Aging Study Amsterdam. MEASUREMENTS: Baseline serum 25(OH)D was determined by a competitive protein binding assay. During 1 yr, falls were prospectively recorded by means of a fall calendar. RESULTS: Low 25(OH)D (<10 ng/ml) was associated with an increased risk of falling. After adjustment for age, sex, education level, region, season, physical activity, smoking, and alcohol intake, the odds ratios (95% confidence interval) were 1.78 (1.06-2.99) for subjects who experienced two falls or more as compared with those who did not fall or fell once and 2.23 (1.17-4.25) for subjects who fell three or more times as compared with those who fell two times or less. There was a statistically significant effect modification by age, and stratified analyses (<75 and > or = 75 yr) showed that the associations were particularly strong in the younger age group; the odds ratios (95% confidence interval) were 5.21 (2.03-13.40) for two falls or more and 4.96 (1.52-16.23) for three falls or more. CONCLUSIONS: Poor vitamin D status is independently associated with an increased risk of falling in the elderly, particularly in those aged 65-75 yr.

Accidental Falls↗

PubMed2006

Inflammatory markers and loss of muscle mass (sarcopenia) and strength.

PURPOSE: The objective of this study was to investigate whether high levels of serum interleukin (IL)-6, C-reactive protein (CRP), and alpha1-antichymotrypsin (ACT) were associated with the loss of muscle strength or muscle mass (sarcopenia) in older persons. SUBJECTS: The study included 986 men and women of the Longitudinal Aging Study Amsterdam, with a mean age of 74.6 years (standard deviation 6.2). METHODS: Grip strength (n = 986) and appendicular muscle mass (n = 328, using dual-energy x-ray absorptiometry) were obtained in 1995 and 1996 and repeated after a 3-year follow-up. Loss of muscle strength was defined as a loss of grip strength greater than 40%, and sarcopenia was defined as a loss of muscle mass greater than 3%, approximating the lowest 15% of the study sample. RESULTS: Multiple linear and logistic regression analyses revealed that higher levels of IL-6 were associated with greater decline in muscle strength, which decreased by -3.21 kg (standard error 0.81) per standard deviation increase in log-transformed IL-6. After adjustment for confounders, including sociodemographic, health, and lifestyle factors, high IL-6 (>5 pg/mL) and high CRP (>6.1 mug/mL) were associated with a 2 to 3-fold greater risk of losing greater than 40% of muscle strength. Persons with high levels of ACT (>181% of the normal human pooled plasma) were 40% less likely to experience loss of muscle strength and tended (P = .07) to have a smaller decline in muscle mass compared with those in the lowest quartile of ACT. No consistent associations of IL-6 and CRP with sarcopenia were found. CONCLUSION: The findings of this prospective, population-based study suggest that higher levels of IL-6 and CRP increase the risk of muscle strength loss, whereas higher levels of ACT decrease the risk of muscle strength loss in older men and women.

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PubMed2005

Homocysteine and vitamin B12 status relate to bone turnover markers, broadband ultrasound attenuation, and fractures in healthy elderly people.

UNLABELLED: Hyperhomocysteinemia may contribute to the development of osteoporosis. The relationship of Hcy and vitamin B12 with bone turnover markers, BUA, and fracture incidence was studied in 1267 subjects of the Longitudinal Aging Study Amsterdam. High Hcy and low vitamin B12 concentrations were significantly associated with low BUA, high markers of bone turnover, and increased fracture risk. INTRODUCTION: Hyperhomocysteinemia may contribute to the development of osteoporosis. Vitamin B12 is closely correlated to homocysteine (Hcy). The main objective of our study was to examine the association of Hcy and vitamin B12 status and the combined effect of these two with broadband ultrasound attenuation (BUA), bone turnover markers, and fracture. MATERIALS AND METHODS: Subjects were 615 men and 652 women with a mean age of 76 +/- 6.6 (SD) years of the Longitudinal Aging Study Amsterdam (LASA). At baseline (1995/1996), blood samples were taken after an overnight fast for dairy products. Plasma Hcy was measured with IMx, serum vitamin B12 with competitive immunoassay (IA) luminescence, serum osteocalcin (OC) with immunoradiometric assay (IRMA), and urinary excretion of deoxypyridinoline (DPD) with competitive IA and corrected for creatinine (Cr) concentration. CVs were 4%, 5%, 8%, and 5%, respectively. BUA was assessed in the heel bone twice in both the right and left calcaneus. Mean BUA value was calculated from these four measurements. CV was 3.4%. After baseline measurements in 1995, a 3-year prospective follow-up of fractures was carried out until 1998/1999. Subjects were grouped by using two different approaches on the basis of their vitamin B12 concentration, normal versus low (<200 pM) or lowest quartile (Q1) versus normal quartiles (Q2-Q4), and Hcy concentration, normal versus high (>15 microM) or highest quartile (Q4) versus normal quartiles (Q1-Q3). Analysis of covariance was performed to calculate mean values of BUA, OC, and DPD/Cr(urine) based on the specified categories of Hcy and vitamin B12 and adjusted for several confounders (potential confounders were age, sex, body weight, body height, current smoking [yes/no], mobility, cognition). The relative risk (RR) of any fracture was assessed with Cox regression analysis. Quartiles were used when Hcy and vitamin B12 were separately studied in their relationship with fracture incidence. RESULTS: Fourteen percent of the men and 9% of the women had high Hcy (>15 microM) and low vitamin B12 (<200 pM) concentrations. Women with vitamin B12 levels <200 pM and Hcy concentrations >15 microM had lower BUA, higher DPD/Cr, and higher OC concentrations than their counterparts. In men, no differences were found between the different Hcy and vitamin B12 categories in adjusted means of BUA, OC, or DPD/Cr(urine). Twenty-eight men and 43 women sustained a fracture during the 3-year follow-up period. The adjusted RR for fractures (95% CI) for men with high Hcy and/or low vitamin B12 concentrations was 3.8 (1.2-11.6) compared with men with normal Hcy and vitamin B12 concentrations. Women with high Hcy and/or low vitamin B12 concentrations had an adjusted RR for fractures of 2.8 (1.3-5.7). CONCLUSIONS: High Hcy and low vitamin B12 concentrations were significantly associated with low BUA, high markers of bone turnover, and increased fracture risk.

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PubMed2005

The association of sex hormone levels with poor mobility, low muscle strength and incidence of falls among older men and women.

OBJECTIVE: The objective of this study was to examine whether low levels of oestradiol and testosterone are associated with impaired mobility, low muscle strength and the incidence of falls in a population-based sample of older men and women. DESIGN: Cross-sectional population-based study, based on data of the Longitudinal Ageing Study Amsterdam (LASA), including 623 men and 663 women, aged 65-88 years. MEASUREMENTS: Serum levels of oestradiol, testosterone, albumin and sex hormone-binding globulin (SHBG) were measured. Physical performance, functional limitations and muscle strength were assessed, and a follow-up on falls was performed prospectively within 3 years. RESULTS: After adjustment for age, level of education, alcohol use, physical activity, chronic disease and body mass index (BMI), men in the highest quartile of the oestradiol/SHBG ratio had significantly higher physical performance scores than men in the lowest quartile (beta = 0.103). Serum levels of total testosterone were positively associated with muscle strength (beta = 0.085). Calculated bioavailable testosterone levels were positively associated with physical performance and muscle strength (beta = 0.128 and 0.109 respectively). No associations of oestradiol levels with mobility were seen in women. Levels of oestradiol and testosterone were not associated with falls. CONCLUSIONS: It can be concluded that low levels of sex hormones were associated with impaired mobility and low muscle strength in men, but not in women. Levels of sex hormones were not associated with the incidence of falls neither in men, nor in women.

Accidental Falls↗

PubMed2005

Late-life anemia is associated with increased risk of recurrent falls.

OBJECTIVES: To examine whether anemia is associated with a higher incidence of recurrent falls. DESIGN: Prospective cohort study. SETTING: Community-dwelling sample in The Netherlands. PARTICIPANTS: Three hundred ninety-four participants aged 65 to 88 from the Longitudinal Aging Study Amsterdam. MEASUREMENTS: Anemia was defined according to World Health Organization criteria as a hemoglobin concentration less than 12 g/dL in women and less than 13 g/dL in men. Falls were prospectively determined using fall calendars that participants filled out weekly for 3 years. Recurrent fallers were identified as those who fell at least two times within 6 months during the 3-year follow-up. RESULTS: Of the 394 persons, 11.9% (18 women and 29 men) had anemia. The incidence of recurrent falls was 38.3% of anemic persons versus 19.6% of nonanemic persons (P=.004). After adjustment for sex, age, body mass index, and diseases, anemia was significantly associated with a 1.91 times greater risk for recurrent falls (95% confidence interval=1.09-3.36). Poor physical function (indicated by muscle strength, physical performance, and limitations) partly mediated the association between anemia and incidence of recurrent falls. CONCLUSION: Late-life anemia is common and associated with twice the risk of recurrent falls. Muscle weakness and poor physical performance appear to partly mediate this association.

Accidental Falls↗

PubMed2004

Homocysteine levels and the risk of osteoporotic fracture.

BACKGROUND: Very high plasma homocysteine levels are characteristic of homocystinuria, a rare autosomal recessive disease accompanied by the early onset of generalized osteoporosis. We therefore hypothesized that mildly elevated homocysteine levels might be related to age-related osteoporotic fractures. METHODS: We studied the association between circulating homocysteine levels and the risk of incident osteoporotic fracture in 2406 subjects, 55 years of age or older, who participated in two separate prospective, population-based studies. In the Rotterdam Study, there were two independent cohorts: 562 subjects in cohort 1, with a mean follow-up period of 8.1 years; and 553 subjects in cohort 2, with a mean follow-up period of 5.7 years. In the Longitudinal Aging Study Amsterdam, there was a single cohort of 1291 subjects, with a mean follow-up period of 2.7 years. Multivariate Cox proportional-hazards regression models were used for analysis of the risk of fracture, with adjustment for age, sex, body-mass index, and other characteristics that may be associated with the risk of fracture or with increased homocysteine levels. RESULTS: During 11,253 person-years of follow-up, osteoporotic fractures occurred in 191 subjects. The overall multivariable-adjusted relative risk of fracture was 1.4 (95 percent confidence interval, 1.2 to 1.6) for each increase of 1 SD in the natural-log-transformed homocysteine level. The risk was similar in all three cohorts studied, and it was also similar in men and women. A homocysteine level in the highest age-specific quartile was associated with an increase by a factor of 1.9 in the risk of fracture (95 percent confidence interval, 1.4 to 2.6). The associations between homocysteine levels and the risk of fracture appeared to be independent of bone mineral density and other potential risk factors for fracture. CONCLUSIONS: An increased homocysteine level appears to be a strong and independent risk factor for osteoporotic fractures in older men and women.

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PubMed2004

Different aspects of visual impairment as risk factors for falls and fractures in older men and women.

UNLABELLED: Visual impairment has been implicated as a risk factor for falling and fractures, but results of previous studies have been inconsistent. The relationship between several aspects of vision and falling/fractures were examined in a prospective cohort study in 1,509 older men and women. The analyses showed that impaired vision is an independent risk factor for both recurrent falling and fractures. INTRODUCTION: Falls and fractures are a major health problem among the elderly. Visual impairment has been implicated as a risk factor for both falls and fractures. However, results from studies are inconsistent. The inconsistency between findings can primarily be attributed to differences in the designs of these studies. Most studies have been cross-sectional or case-control studies, and many have not correctly adjusted for potential confounders. Furthermore, until now, the potential mediating effects of functional limitation, physical performance, and physical activity have not been examined. MATERIALS AND METHODS: A total of 1,509 people was examined in 1995-1996. Contrast sensitivity was assessed with the VCTS_6000-1 chart for near vision. In addition, self-reported visual impairment was assessed by questions on recognizing faces from a distance of 4 m, reading the small print in the newspaper, and problems with glare. Furthermore, many potential confounders and mediators were assessed. Falls and fractures were assessed prospectively during a 3-year follow-up period. The associations between the vision variables and falls and fractures were examined using Cox proportional hazards analyses. RESULTS: After adjustment for potential confounders, contrast sensitivity was shown to be associated with recurrent falling (hazard ratio [HR] = 1.5), and the question on recognizing faces was shown to be associated with fractures (HR = 3.1). Furthermore, functional limitations and physical performance were shown to be mediators in the relationship between vision variables and recurrent falling/fractures. CONCLUSIONS: The results indicate that impaired vision is an independent risk factor for falling and fractures, but different aspects of visual functioning may have different relationships to falling and fractures.

Accidental Falls↗

PubMed2004

Comparison of the LASA Physical Activity Questionnaire with a 7-day diary and pedometer.

OBJECTIVE: First, to validate the LASA Physical Activity Questionnaire (LAPAQ) by a 7-day diary and a pedometer in older persons. Second, to assess the repeatability of the LAPAQ. Third, to compare the feasibility of these methods. STUDY DESIGN AND SETTING: The study was performed in a subsample (n=439, aged 69-92 years) of the Longitudinal Aging Study Amsterdam (LASA). The LAPAQ was completed twice (1998/1999, 1999/2000). Respondents completed a 7-day activity diary and wore a pedometer for 7 days (1999/2000). RESULTS: The LAPAQ was highly correlated with the 7-day diary (r=0.68, P<.001), and moderately with the pedometer (r=0.56, P<.001). The repeatability of the LAPAQ was reasonably good (weighted kappa: 0.65-0.75). The LAPAQ was completed in 5.7+/-2.7 min, and 0.5% of the respondents had missing values. CONCLUSION: The LAPAQ appears to be a valid and reliable instrument for classifying physical activity in older people. The LAPAQ was easier to use than the 7-day diary and pedometer.

Activities of Daily Living↗

PubMed2004

Consequences of falling in older men and women and risk factors for health service use and functional decline.

OBJECTIVES: (1) to examine consequences of falls in older men and women and (2) to examine risk factors for health service use and functional decline among older fallers. METHODS: the study was performed within the Longitudinal Aging Study Amsterdam. In 1998/1999, potential risk factors were assessed during the third data collection. In 1999/2000, 204 community-dwelling persons (> or =65 years) who reported at least one fall in the year before the interview, were asked about consequences of their last fall, including physical injury, health service use, treatment and functional decline (i.e. decline in functional status, social and physical activities). RESULTS: as a consequence of falling, respondents reported physical injury (68.1%), major injury (5.9%), health service use (23.5%), treatment (17.2%), and decline in functional status (35.3%), and social (16.7%) and physical activities (15.2%). Using multivariate logistic regression, specific risk factors for health service use after falling could not be identified. Female gender (OR = 2.8, 95% CI = 1.5-5.1), higher medication use (OR = 1.5, 95% CI = 1.0-2.2) and depressive symptoms (OR = 1.9, 95% CI = 1.3-2.8) were independently associated with functional decline after falling. Depressive symptoms (OR = 2.0, 95% CI = 1.2-3.3) and falls inside (OR = 2.6, 95% CI = 1.1-6.5) were risk factors for decline in social activities, while female gender (OR = 2.7, 95% CI = 1.1-7.0) and depressive symptoms (OR = 1.9, 95% CI = 1.2-3.0) were risk factors for decline in physical activities after falling. CONCLUSIONS: almost 70% of the respondents suffered physical injury, almost one-quarter used health services and more than one-third suffered functional decline after falling. No risk factors were found for health service use needed after falling. Female gender, higher medication use, depressive symptoms and falls inside were risk factors for functional decline after falling.

Accidental Falls↗

PubMed2003

Cross-national determinants of quality of life from six longitudinal studies on aging: the CLESA project.

BACKGROUND AND AIMS: The Comparison of Longitudinal European Studies on Aging (CLESA) Project, here presented for the first time, is a collaborative study involving five European and one Israeli longitudinal study on aging. The aim of this paper is to describe the methodology developed for the harmonization of data and the creation of a Common Data Base (CDB), and to investigate the distribution of some selected common variables among the six countries. The design of each study is briefly introduced and the methodology leading to the harmonization of the common variables is described. METHODS: The study base includes data from five European countries (Finland, Italy, the Netherlands, Spain, Sweden) and Israel, for older people aged 65-89 living both in the community and in institutions (total, 11557 subjects). For two age classes (65-74 and 75-84), the prevalence ratios or the mean values of the following selected variables are provided: a) sociodemographic variables; b) health habits; c) health status; d) physical functioning; e) social networks and support; and f) health and social services utilization. RESULTS: Statistically significant differences were found between most of the investigated characteristics across the CLESA countries, with very few exceptions. While some of the differences found may be due to cultural variations, others require further investigation and should be encompassed in the main framework of the Project, which is to identify predictors of hospitalization, mortality, institutionalization and functional decline. CONCLUSIONS: A common data base is available for the study of the aging process in five European and one Israeli population. These data provide a unique opportunity to identify common risk factors for mortality and functional decline and increase our understanding of country-specific exposures and vulnerability.

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PubMed2003

Are IADLs comparable across countries? Sociodemographic associates of harmonized IADL measures.

BACKGROUND AND AIMS: Independence in Instrumental Activities of Daily Living (IADLs) is determined not only by physical ability but also by the environmental and cultural surroundings of the individual. The present study describes the harmonization of data on IADL functioning of the Comparison of Longitudinal European Studies on Aging (CLESA) Project. The focus of this report is to examine the comparability of IADLs across countries and to study the association of IADLs with age, gender and socioeconomic status, and the scalability of the measure. METHODS: The study base includes data from five European countries (Finland, Italy, The Netherlands, Spain, Sweden) and Israel, for older people aged 65-89 living both in the community and in institutions, for a total of 11,557 subjects. In this report, only community-dwelling respondents were included (N=8420). The common IADL items in all six countries were: preparing meals, shopping, and doing housework. The analyses include how these items are distributed by age group and gender, and the associations between independence in these items and socioeconomic status (SES) with logistic regression modeling. The scale properties of these three items are also examined. RESULTS: Independence in IADLs decreases steadily with age in all countries. Associations with gender and SES follow largely similar patterns across countries. The reliability of the 3-item scale is satisfactory in most countries, and Cronbach's alpha-coefficient for the complete CLESA sample was 0.75. CONCLUSIONS: The associations between sociodemographic variables and independence in preparing meals, shopping, and doing housework are similar across countries. Results suggest that the predictors of IADLs in different countries are comparable.

Activities of Daily Living↗

PubMed2003

Balance and mobility performance as treatable risk factors for recurrent falling in older persons.

BACKGROUND AND OBJECTIVES: The purpose of this study was to examine whether easily measurable measures for balance and muscle strength predicted recurrent falling as well as sophisticated measurements, and to examine which of the modifiable risk factors were strongest associated with recurrent falling. METHODS: The study was performed in a subsample (n=439, aged 69-92 years) of the Longitudinal Aging Study Amsterdam (LASA). Balance, muscle strength, physical activity, and performance tests were assessed. Falls were recorded during 1 year. The outcome measure was recurrent falls (>/=2 falls within 1 year). RESULTS: The area under the curve (AUC) of mediolateral sway (AUC=0.67; 95% CI:0.57-0.77), tandem stand (AUC=0.61; 95% CI:0.49-0.73), leg extension strength (AUC=0.58; 95% CI:0.51-0.64), and handgrip strength (AUC=0.57; 95% CI:0.51-0.64) for recurrent falling were not significantly different. In a multivariate model, mediolateral sway (OR=2.8; 95% CI:1.1-6.9), tandem stand (OR=2.1; 95% CI:1.1-3.8), and walking test (OR=2.2; 95% CI:1.1-4.1) were significantly associated with recurrent falling. CONCLUSIONS: The easily measurable tandem stand and handgrip strength predicted recurrent falling as well as the sophisticated measures. Mediolateral sway was strongest associated with recurrent falling.

Accidental Falls↗

PubMed2003

A classification tree for predicting recurrent falling in community-dwelling older persons.

OBJECTIVES: To develop a classification tree for predicting the risk of recurrent falling in community-dwelling older persons using tree-structured survival analysis (TSSA). DESIGN: A prospective cohort study. SETTING: A community in the Netherlands. PARTICIPANTS: One thousand three hundred sixty-five community-dwelling older persons (>/=65) from the Longitudinal Aging Study Amsterdam (LASA). MEASUREMENTS: In 1995, physical, cognitive, emotional, and social aspects of functioning were assessed. Subsequently, a prospective fall follow-up, specifically on recurrent falls (two falls within 6 months) was conducted for 3 years. RESULTS: The classification tree included 11 end groups differing in risk of recurrent falling based on a minimum of two and a maximum of six predictors. The first split in the tree involved two or more falls versus fewer than two falls in the year preceding the interview. Respondents with two or more falls in the year preceding the interview (n=193) and with at least two functional limitations (n=98) had a 75% risk of becoming a recurrent faller, whereas respondents with fewer than two functional limitations were further divided into a group with regular dizziness (n=11, risk of 68%) and a group with no regular dizziness (n=84, risk of 30%). In respondents with fewer than two falls in the year preceding the interview (n=1,172), the risk of becoming a recurrent faller varied between 9% and 70%. Predictors in this branch of the tree were low performance, low handgrip strength, alcohol use, pain, high level of education, and high level of physical activity. CONCLUSION: This classification tree included 11 end groups differing in the risk of recurrent falling based on specific combinations of a maximum of six easily measurable predictors. The classification tree can identify subjects who are eligible for preventive measures in public health strategies.

Accidental Falls↗

PubMed2002

Different cognitive functions in relation to falls among older persons. Immediate memory as an independent risk factor for falls.

It is not clear which specific cognitive function is strongest related to falls. To investigate this, not only "general cognitive functioning," but also "nonverbal and abstract reasoning," "information processing speed," and "immediate memory" were related to falls. Furthermore, relevant effect modifiers, confounders, and mediators were identified. This study was performed within the Longitudinal Aging Study Amsterdam (LASA), a multidisciplinary, prospective cohort study. In this study (n = 1437), an interaction between "immediate memory" and age was found. In persons aged 75 years and over, "immediate memory," as measured by the 15 Words Test, showed to be an independent risk factor for falls. Part of this relationship was explained by the mediating effects of activity, mobility, and grip strength. The association between the other cognitive functions and falls was only statistically significant in univariate analysis. We conclude that "immediate memory" is an independent risk factor for recurrent falls in persons aged 75 years and older.

Accidental Falls↗

PubMed2002

Physical activity as a determinant of change in mobility performance: the Longitudinal Aging Study Amsterdam.

OBJECTIVES: This study examined the association of (change in) physical activity and decline in mobility performance in older men and women. DESIGN: A 3-year prospective study using data of the Longitudinal Aging Study. SETTING: Netherlands. PARTICIPANTS: Two thousand one hundred nine men and women aged 55 to 85. MEASUREMENTS: Total physical activity (expressed as hours per day and kilocalories per day) and sports participation were measured using a validated, interviewer-administered questionnaire. Mobility performance was assessed using two timed tests: 6-meter walk and repeated chair stands. RESULTS: Mobility performance declined for 45.6% of the sample. At baseline, the mean time +/- standard deviation spent on total physical activity was 3.0 +/- 2.1 h/d or 719 +/- 543 kcal/d, and 56.6% of the sample participated in sports. Sports participation and a higher level of total physical activity, walking, or household activity were associated with a smaller mobility decline. After 3 years, total physical activity declined, and only 53.4% of those reporting sports at baseline continued doing so. Continuation of physical activity over time was associated with the smallest decline in mobility. The observed associations were similar for those with and without chronic disease (P> 0.3). The conclusions did not change after adjustment for potential confounders, including demographic and lifestyle variables, depression, and cognitive status. CONCLUSIONS: Physical activity, and especially a regularly active lifestyle, may slow the decline in mobility performance. A beneficial effect was observed for sports and nonsports activities, independent of the presence of chronic disease.

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PubMedDate not supplied

Insulin-like growth factor I (IGF-I) and cognitive decline in older persons.

Insulin-like growth factor I (IGF-I) deficiency may be involved in cognitive deficits seen with aging, and in neurodegenerative diseases such as Alzheimer's disease. The objective of this study was to investigate whether IGF-I is associated with cognitive performance and 3-year cognitive decline in 1318 subjects, aged 65-88 years. Cross-sectionally, IGF-I was directly related to information processing speed, memory, fluid intelligence, and Mini-Mental State Examination (MMSE) score, but these associations did not remain significant after adjustment for age and other factors. Analysis in quintiles of IGF-I revealed a threshold effect of low IGF-I on information processing speed, with lower speed in subjects in the lowest quintile of IGF-I (<9.4 nmol/l)(1) versus those in the other four quintiles (fully adjusted B=-0.89; 95% CI, -1.72 to -0.05). This threshold of low IGF-I was also observed for 3-year decline in information processing speed (adjusted RR=1.78; 95% CI, 1.19-2.68). In summary, this study suggests that IGF-I levels below 9.4 nmol/l are negatively associated with both the level and decline of information processing speed.

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