Biomedical subjects

David Melzer

Publications and source records attributed to David Melzer.

At least 19 recordsLinked to original sources

PubMed2007

What level of alcohol consumption is hazardous for older people? Functioning and mortality in U.S. and English national cohorts.

OBJECTIVES: To estimate disability plus mortality risks in older people according to level of alcohol intake. DESIGN: Two population-based cohort studies. SETTING: The Health and Retirement Study (United States) and the English Longitudinal Study of Aging (England). PARTICIPANTS: Thirteen thousand three hundred thirty-three individuals aged 65 and older followed for 4 to 5 years. MEASUREMENTS: Difficulties with activities of daily living (ADLs), instrumental activities of daily living (IADLs), poor cognitive function, and mortality. RESULTS: One-tenth (10.8%) of U.S. men, 28.6% of English men, 2.9% of U.S. women, and 10.3% of English women drank more than the U.S. National Institute on Alcohol Abuse and Alcoholism recommended limit for people aged 65 and older. Odds ratios (ORs) of disability, or disability plus mortality, in subjects drinking an average of more than one to two drinks per day were similar to ORs in subjects drinking an average of more than none to one drink per day. For example, those drinking more than one to two drinks per day at baseline had an OR of 1.0 (95% confidence interval (CI)=0.8-1.2) for ADL problems, 0.7 (95% CI=0.6-1.0) for IADL problems, and 0.8 (95% CI=0.6-1.1) for poor cognitive function. Findings were robust across alternative models. The shape of the relationship between alcohol consumption and risk of disability was similar in men and women. CONCLUSION: Functioning and mortality outcomes in older people with alcohol intakes above U.S. recommended levels for the old but within recommendations for younger adults are not poor. More empirical evidence of net benefit is needed to support screening and intervention efforts in community-living older people with no specific contraindications who drink more than one to two drinks per day.

Accidental Falls↗

PubMed2006

Effects of the diabetes linked TCF7L2 polymorphism in a representative older population.

BACKGROUND: A polymorphism in the transcription factor 7-like 2 (TCF7L2) gene has been found to be associated with type 2 diabetes in case-control studies. We aimed to estimate associations of the marker rs7903146 (C/T) polymorphism with fasting glucose, lipids, diabetes prevalence and complications in an older general population. METHODS: In total, 944 subjects aged > or = 65 years from the population representative InCHIANTI study were enrolled in this study. Those with fasting blood glucose of > or = 7 mmol/l or physician diagnosis were considered diabetic. Cut-off points for impaired fasting glucose (IFG) were > or = 5.6 mmol/l to < 7 mmol/l. RESULTS: In the general population sample, minor (T) allele carriers of rs7903146 had higher fasting blood glucose (FBG) (p = 0.028) but lower fasting insulin (p = 0.030) and HOMA2b scores (p = 0.001), suggesting poorer beta-cell function. T allele carriers also had smaller waist circumference (p = 0.009), lower triglyceride levels (p = 0.006), and higher high-density lipoprotein cholesterol (p = 0.008). The prevalence of diabetes or IFG was 32.4% in TT carriers and 23.3% in CC carriers; adjusted OR = 1.67 (95% confidence interval 1.05 to 2.65, p = 0.031). Within the diabetic and IFG groups, fewer T allele carriers had metabolic syndrome features (p = 0.047) or had experienced a myocardial infarction (p = 0.037). Conversely, T allele carriers with diabetes had poorer renal function (reduced 24-hour creatinine clearance, p = 0.013), and possibly more retinopathy (p = 0.067). Physician-diagnosed dementia was more common in the T carriers (in diabetes p = 0.05, with IFG p = 0.024). CONCLUSION: The TCF7L2 rs7903146 polymorphism is associated with lower insulin levels, smaller waist circumference, and lower risk lipid profiles in the general elderly population. Patients with diabetes who are carriers of the minor allele are less likely to have metabolic-syndrome features, but may experience more microvascular complications, although the number of cases was small. If replicated, these findings may have implications for developing treatment approaches tailored by genotype.

Aged↗

PubMed2006

A common haplotype of the glucokinase gene alters fasting glucose and birth weight: association in six studies and population-genetics analyses.

Fasting glucose is associated with future risk of type 2 diabetes and ischemic heart disease and is tightly regulated despite considerable variation in quantity, type, and timing of food intake. In pregnancy, maternal fasting glucose concentration is an important determinant of offspring birth weight. The key determinant of fasting glucose is the enzyme glucokinase (GCK). Rare mutations of GCK cause fasting hyperglycemia and alter birth weight. The extent to which common variation of GCK explains normal variation of fasting glucose and birth weight is not known. We aimed to comprehensively define the role of variation of GCK in determination of fasting glucose and birth weight, using a tagging SNP (tSNP) approach and studying 19,806 subjects from six population-based studies. Using 22 tSNPs, we showed that the variant rs1799884 is associated with fasting glucose at all ages in the normal population and exceeded genomewide levels of significance (P=10-9). rs3757840 was also highly significantly associated with fasting glucose (P=8x10-7), but haplotype analysis revealed that this is explained by linkage disequilibrium (r2=0.2) with rs1799884. A maternal A allele at rs1799884 was associated with a 32-g (95% confidence interval 11-53 g) increase in offspring birth weight (P=.002). Genetic variation influencing birth weight may have conferred a selective advantage in human populations. We performed extensive population-genetics analyses to look for evidence of recent positive natural selection on patterns of GCK variation. However, we found no strong signature of positive selection. In conclusion, a comprehensive analysis of common variation of the glucokinase gene shows that this is the first gene to be reproducibly associated with fasting glucose and fetal growth.

Adult↗

PubMed2006

The functional "KL-VS" variant of KLOTHO is not associated with type 2 diabetes in 5028 UK Caucasians.

BACKGROUND: Klotho has an important role in insulin signalling and the development of ageing-like phenotypes in mice. The common functional "KL-VS" variant in the KLOTHO (KL) gene is associated with longevity in humans but its role in type 2 diabetes is not known. We performed a large case-control and family-based study to test the hypothesis that KL-VS is associated with type 2 diabetes in a UK Caucasian population. METHODS: We genotyped 1793 cases, 1619 controls and 1616 subjects from 509 families for the single nucleotide polymorphism (SNP) F352V (rs9536314) that defines the KL-VS variant. Allele and genotype frequencies were compared between cases and controls. Family-based analysis was used to test for over- or under-transmission of V352 to affected offspring. RESULTS: Despite good power to detect odds ratios of 1.2, there were no significant associations between alleles or genotypes and type 2 diabetes (V352 allele: odds ratio = 0.96 (0.84-1.09)). Additional analysis of quantitative trait data in 1177 healthy control subjects showed no association of the variant with fasting insulin, glucose, triglycerides, HDL- or LDL-cholesterol (all P > 0.05). However, the HDL-cholesterol levels observed across the genotype groups showed a similar, but non-significant, pattern to previously reported data. CONCLUSION: This is the first large-scale study to examine the association between common functional variation in KL and type 2 diabetes risk. We have found no evidence that the functional KL-VS variant is a risk factor for type 2 diabetes in a large UK Caucasian case-control and family-based study.

Adult↗

PubMed2006

Low prevalence of depression and anxiety is linked to statutory retirement ages rather than personal work exit: a national survey.

BACKGROUND: Common mental disorder prevalence decreases substantially around the conventional retirement age for men in the UK, but trends for older women are more continuous. Prevalence changes in depression and anxiety around retirement are less clear, as is the role of risk factors. The aim of this study was to establish whether work status, age or other known risk factors account for the reduced prevalence of depressive episode and anxiety disorder around retirement ages for men and for women. METHOD: The British Psychiatric Morbidity Survey (BPMS) 2000 was analysed, including 1875 men and 2253 women aged 45-75 years. Diagnoses were from the Revised Clinical Interview Schedule (CIS-R). Logistic models were adjusted for sociodemographic factors, social network, work status, life events, physical illness and disability. RESULTS: There are marked reductions in the prevalence of depressive episode after 60 years for women [60% lower prevalence, 95% confidence interval (CI) 40-80] and 65 years for men (90% lower prevalence, 95% CI 70-100), compared to the youngest age groups. For anxiety disorder, the reduction in prevalence was 80% (95% CI 60-90) for men and 40% (95% CI 20-60) for women. In fully adjusted multivariate models, the strong association between diagnoses and age groups remained, for both genders. Work status was a significant factor for men but not for women. CONCLUSION: There is a discontinuity in the prevalence of depressive episode for both men and women, coinciding with statutory retirement ages. No studied risk factor reduced the associations between age group and disorders. This population scale recovery may provide a model for understanding non-genetic factors.

Aged↗

PubMed2006

Mental health and the timing of men's retirement.

BACKGROUND: Analysis of the Psychiatric Morbidity Survey of Great Britain showed that the prevalence of common mental disorders was lower amongst men at or above Britain's state pension age of 65, relative to younger men. Retirees below this age had consistently higher rates of mental disorders than working men. In contrast, the low prevalence of mental disorders amongst retirees aged 65 and older was similar to that of their working peers. The aim of this analysis was to investigate this pattern of results in a national sample of Australian men, and the mediating role of socio-demographic factors. METHOD: Data were from the Household, Income and Labour Dynamics (HILDA) in Australia survey (2003). The analyses included men aged 45-74 years who were active in the labour force (n = 1309), or retired (n = 635). Mental health was assessed using the mental health scale from the Short-Form 36 Health Questionnaire. RESULTS: Retirees were more likely to have mental health problems than their working peers, however this difference was progressively smaller across age groups. For retirees above, though not below, the age of 55 this difference was explained by poorer physical functioning. When age at retirement was considered it was found that early retirees who were now at or approaching the conventional retirement age did not display the substantially elevated rates of mental health problems seen in their younger counterparts. Further, men who had retired at age 60 or older did not display an initially elevated rate of mental health problems. CONCLUSIONS: The association between retirement and mental health varies across older adulthood. Retired British and Australian men below the conventional retirement age of 65 are more likely to have mental health problems relative to their working peers, and retirees above this age. However, poor mental health appears to be linked to being retired below this age rather than an enduring characteristic of those who retire early.

Age Factors↗

PubMed2006

Middle-aged and mobility-limited: prevalence of disability and symptom attributions in a national survey.

BACKGROUND: Lower limb mobility disabilities are well understood in older people, but the causes in middle age have attracted little attention. OBJECTIVES: To estimate the prevalence of mobility disabilities among noninstitutionalized adults in England and to compare the disabling symptoms reported by middle-aged and older people. DESIGN: Cross-sectional data from the 2002 English Longitudinal Study of Ageing (ELSA). Mobility disability was identified by level of reported difficulty walking a quarter mile. PARTICIPANTS: Eleven thousand two hundred sixteen respondents aged 50 years and older living in private households in 2002. RESULTS: The prevalence of difficulty walking a quarter mile increases sharply with age, but even in the middle-aged (50 to 64 years age-group) 18% (95% confidence interval [CI]: 16% to 19%) of men and 19% (95% CI: 17% to 20%) of women reported some degree of difficulty. Of the 16 main symptoms reported as causing mobility disability in middle age, 2 dominated: pain in the leg or the foot (43%; 95% CI: 40% to 46%) and shortness of breath/dyspnea (21%; 95% CI: 18% to 23%). Fatigue or tiredness, and stability problems were cited by only 5% and 6%, respectively. These proportions were slightly different from those in the 65 to 79-year age group: 40%, 23%, 6%, and 8%, respectively. CONCLUSIONS: Mobility (walking) disabilities in the middle-aged are relatively common. The symptoms reported as causes in this age group differ little from those reported by older groups, and are dominated by lower limb pain and shortness of breath. More clinical attention paid to disabling symptoms may lead to disability reductions in later life.

Activities of Daily Living↗

PubMed2005

Retirement and mental health: analysis of the Australian national survey of mental health and well-being.

Nation-wide research on mental health problems amongst men and women during the transition from employment to retirement is limited. This study sought to explore the relationship between retirement and mental health across older adulthood, whilst considering age and known risk factors for mental disorders. Data were from the 1997 National Survey of Mental Health and Well-being, a cross-sectional survey of 10,641 Australian adults. The prevalence of depression and anxiety disorders was analysed in the sub-sample of men (n = 1928) and women (n = 2261) aged 45-74 years. Mental health was assessed using the Composite International Diagnostic Instrument. Additional measures were used to assess respondents' physical health, demographic and personal characteristics. The prevalence of common mental disorders diminished across increasing age groups of men and women. Women aged 55-59, 65-69, and 70-74 had significantly lower rates of mental disorders than those aged 45-49. In contrast, only men aged 65-69 and 70-74 demonstrated significantly lower prevalence compared with men aged 45-49. Amongst younger men, retirees were significantly more likely to have a common mental disorder relative to men still in the labour force; however, this was not the case for retired men of, or nearing, the traditional retirement age of 65. Men and women with poor physical health were also more likely to have a diagnosable mental disorder. The findings of this study indicate that, for men, the relationship between retirement and mental health varies with age. The poorer mental health of men who retire early is not explained by usual risk factors. Given current policy changes in many countries to curtail early retirement, these findings highlight the need to consider mental health, and its influencing factors, when encouraging continued employment amongst older adults.

Age Factors↗

PubMed2005

The distribution of the common mental disorders: social inequalities in Europe.

BACKGROUND: The social class distribution of the common mental disorders (mostly anxiety and/or depression) has been in doubt until recently. This paper reviews the evidence of associations between the prevalence of the common mental disorders in adults of working age and markers of socio-economic disadvantage. METHODS: Work is reviewed which brings together major population surveys from the last 25 years, together with work trawling for all European population studies. Data from more recent studies is examined, analysed and discussed. Because of differences in methods, instruments and analyses, little can be compared precisely, but internal associations can be examined. FINDINGS: People of lower socio-economic status, however measured, are disadvantaged, and this includes higher frequencies of the conditions now called the 'common mental disorders' (mostly non-psychotic depression and anxiety, either separately or together). In European and similar developed populations, relatively high frequencies are associated with poor education, material disadvantage and unemployment. CONCLUSION: The large contribution of the common mental disorders to morbidity and disability, and the social consequences in working age adults would justify substantial priority being given to addressing mental health inequalities, and deprivation in general, within national and European social and economic policy.

Journal Article↗

PubMed2005

[Disability among elderly women in Brazil].

OBJECTIVE: To estimate disability rates and explore associations, identifying the most significant socioeconomic markers associated with the prevalence of mobility disability among elderly women. METHODS: National mobility disability rates were estimated based on information from the 1998 National Household Survey (PNAD), conducted by the Instituto Brasileiro de Geografia e Estatística. The present study analyzes the elderly women population, totaling 16,186 subjects. Logistic regression models were constructed considering 'difficulty walking 100 meters' as the dependent variable. RESULTS: The prevalence of markers of mild, moderate and severe disability was greater among women, and increased with age. In logistic regression analysis, markers most strongly associated with increased prevalence of mobility disability were age, gender, low schooling, and low income. Rural residence was also associated with reduced prevalence. CONCLUSIONS: Our results suggest potential risk factors for the development of functional decline in elderly women, given that the associations encountered were consistent with those reported by other studies in the literature.

Activities of Daily Living↗

PubMed2005

The mental health of early retirees-- national interview survey in Britain.

BACKGROUND: There is intense political interest in retaining older workers in the workforce, to fund lengthening retirements. While health is important in early exit from work, the health of early retirees has been little studied. OBJECTIVE: The aim of this study was to compare the health status of economically active 50- to 64-year-olds with economically inactive former workers (termed early retirees). METHODS: A total of 1,875 respondents to the 2000 Psychiatric Morbidity Survey of Great Britain were included in the analysis. Current common mental (neurotic) disorder presence was based on the revised Clinical Interview Schedule (CIS-R). RESULTS: Results In all, 71.2% of men and 66.4% of women early retirees reported having a long-standing illness. Of early retired men, 22.2% have a common mental disorder compared to 8.2% of those still in work (p value of difference<0.001). In contrast, the respective figures for women were 18.2% and 16.9%. In fully adjusted regression models for men, early retirees were more likely to have generalised anxiety disorders (OR 3.1: 95% CI: 1.2-7.8) and depressive disorders (OR 4.3: 95% CI: 1.7-11.0). CONCLUSION: There is a substantial burden of specific mental health disorders in early retiree men. Understanding the mechanisms of this excess of mental disorders in early retiree men may be a prerequisite to increasing the numbers seeking or staying in work up to age 65.

Adolescent↗

PubMed2005

Mobility disability in the middle-aged: cross-sectional associations in the English Longitudinal Study of Ageing.

BACKGROUND: Mobility (locomotor) disability is an early marker of disability progression, health care utilisation and institutionalisation in older people. Whether mobility disability has different causes in the middle-aged has received limited attention. OBJECTIVES: To examine associations of mobility disability with sociodemographic, behaviour and disease status and to contrast these with associations in older groups. DESIGN: Cross-sectional interview data from the 2002 English Longitudinal Study of Ageing. Mobility status based on reported difficulty walking a quarter of a mile (402 m). PARTICIPANTS: A total of 11,392 community-living respondents aged 50 years and over. RESULTS: In the middle-aged, 8% (95% CI 7-9%) of women and 9% (95% CI 8-11%) of men reported having much difficulty or being unable to walk a quarter of a mile, equating to 787,000 (95% CI 700,000-831,000) people in England. Factors which at least doubled odds of mobility disability in the middle-aged were chronic obstructive lung disease, angina, stroke, recently treated cancer, comorbidity, lower limb and back pain. Factors associated with mobility disability in older groups were similar. Thirty-eight per cent of mobility disability in the middle-aged population was related to high levels of lower limb pain and 15% to high levels of back pain. CONCLUSIONS: Mobility disability in the middle-aged is relatively common. The associated conditions in the middle-aged are similar to those in older people. Lower limb and back pain make dominant population contributions to mobility disability. Prevention of later disability progression may require more attention being paid to mobility difficulties and its causes in the middle-aged.

Aged↗

PubMed2005

The apolipoprotein E e4 polymorphism is strongly associated with poor mobility performance test results but not self-reported limitation in older people.

BACKGROUND: The apolipoprotein E (ApoE) e4 polymorphism is linked to increased mortality rates, Alzheimer's disease, and cardiovascular disease in older people, but previous studies have largely failed to detect an effect on self-reported mobility disability. We hypothesized that poor performance on mobility-related tests may provide a better measure of effects, and we aimed to estimate the extent to which the ApoE e4 allele increases risks of poor performance on measured mobility and self-reported mobility disability compared to e3/3, in a medium-sized population cohort. METHODS: Data were from 1262 people at baseline older than 65 years from the Longitudinal Aging Study Amsterdam (LASA), followed up for 6 years. Age- and sex-adjusted logistic regression models were used to explore associations. RESULTS: At baseline, those individuals with an e4 allele had an odds ratio of 2.26 (95% confidence interval, 1.31-3.90) for poor performance on gait speed testing (<0.4 m/s) and 1.94 (95% confidence interval, 1.19-3.16) for five chair stands (> or =20 s), compared to those with e3/3 status. At follow-up, associations between e4 status and incident poor performance on the chair stand test was significant. Associations with self-reported inability or need for help walking for 5 minutes or for climbing 15 steps were nonsignificant throughout. CONCLUSIONS: The ApoE e4 polymorphism is associated with a substantial excess of mobility limitation. The impact is detectable by performance testing, but not by self-reports. Poor results on mobility performance tests may provide a phenotype of ageing.

Aged↗

PubMed2005

Psychosis in the community and in prisons: a report from the British National Survey of psychiatric morbidity.

OBJECTIVE: Reports of increased rates of psychosis in prisons could be due to sampling and ascertainment differences. The authors compared two samples of subjects 16-64 years of age: those from the general population of residents in Great Britain and prisoners in England and Wales. METHOD: A random sample of remanded and sentenced male and female prisoners (N=3,142) and a two-phase, cross-sectional random sample of household residents (N=10,108) were assessed with structured questionnaires and the semistructured Schedules for Clinical Assessment in Neuropsychiatry. RESULTS: The weighted prevalence of probable functional psychosis in the past year was 4.5 per thousand (95% CI=3.1 to 5.8) in the household survey. In the prison survey, the weighted prevalence was over 10 times greater: 52 per thousand (95% CI=45 to 60). One in four prisoners with a psychotic disorder had psychotic symptoms attributed to toxic or withdrawal effects of psychoactive substances. The proportion of subjects with specific types of hallucinations or delusions did not differ between prison and household psychosis cases. CONCLUSIONS: This large study using standardized comparisons showed that the prevalence of psychosis in prisons is substantially higher than in the community and is deserving of greater attention to treatment and prevention. Apart from a minority of prisoners with symptoms attributable to psychoactive substances, the clinical symptom profile of psychosis is the same in both settings. Longitudinal research is needed to better understand these prevalence differences.

Adolescent↗

PubMed2005

Pharmacogenetics: policy needs for personal prescribing.

Pharmacogenetics involves genetic testing of individual patients to guide drug treatment. Proponents argue that pharmacogenetics will achieve major gains in drug safety and efficacy, and revolutionise marketing. Pharmacogenetics also raises several policy concerns, including the need for sound information for clinical decision-making on drug-genetic test combinations. Currently, the pharmacogenetics science base and the rate of emergence of clinical applications are uncertain. Most commentary on pharmacogenetics focuses on new compounds, yet older drugs cause most adverse events. Test regulation in the USA appears fundamentally different from Europe, where evidence of safety or efficacy may not be required. Genetics research is needed as part of post-marketing surveillance systems. In routine clinical practice, computer-based health records with relevant decision support systems will also be needed. Without health policy action, pharmacogenetics could produce a new generation of poorly evaluated tests and drugs, with medicine becoming significantly less evidence-based, leading to rising costs, patient hazard and exclusions of drug-related 'genetic minorities' from evaluated treatments.

Drug Approval↗

PubMed2004

Decline in Common Mental Disorder prevalence in men during the sixth decade of life. Evidence from the National Psychiatric Morbidity Survey.

BACKGROUND: The impact of social transitions that might improve mental health, such as retirement, has attracted limited attention. Adverse occupational conditions and involuntary exit from work are linked to high rates of common mental disorders, but voluntary retirement is associated with improved mental health. AIMS: We aimed to estimate the prevalence of common mental disorders around the conventional retirement age and to identify the associated factors that might explain differences in rates. METHODS: Data were from the Psychiatric Morbidity Survey of Great Britain (2000), covering a sample of 8,580 respondents aged 16-74 years. Current common mental (neurotic) disorder presence was based on the revised Clinical Interview Schedule. RESULTS: Prevalence rates for having any common mental disorder in men aged 65-69 years (5%; 95% CI: 2.7-7.3) were dramatically lower than in the agegroup 60-64 years (14.5%; 95 % CI: 10.6-18.5). This pattern applied to individual disorders and to the prevalence of very high symptoms counts. Prevalence rates in women peaked at age 50 and declined thereafter, but no large changes in prevalence are evident around age 60 or 65 years. In men leaving work early (aged 50-64 years), prevalence of common mental disorders remains high until the conventional retirement age. There is little change in exposure to other studied risk factors capable of explaining prevalence reduction, with the exception of decreased economic hardship in the older group. CONCLUSION: In the general population aged 50-74 years,there is a dramatic improvement in mental health in men after the conventional retirement age, but not in women. In men who leave work earlier, prevalence remains relatively high until after age 65.

Adolescent↗

PubMed2004

Socio-demographic correlates of mobility disability in older Brazilians: results of the first national survey.

INTRODUCTION: Socio-economic differences in mobility disability prevalence in old age have been reported from the US and Europe. Brazil is characterised by gross socio-economic inequalities, but there have been no previous national data on disability prevalence. AIM: This study aimed to estimate disability rates and explore associations identifying the most significant socio-economic markers associated with mobility disability prevalence in old age in Brazil. SUBJECTS AND METHODS: A nationally representative sample of 28,943 people aged 60 years or over was interviewed, in the 1998 National Household Survey (PNAD), conducted by the Brazilian Institute of Geography and Statistics. RESULTS: The prevalence rates of markers of mild, moderate and severe disability were higher in women than men, and increased with age. Prevalence rates of difficulty with personal care and medium distance walking were broadly similar to England, but far more Brazilians reported difficulty climbing stairs. In logistic regression analyses, the strongest markers associated with increased mobility disability prevalence were age, gender, lack of education and low income. Rural residence was also associated with reduced prevalence. Limited differences by region were present, and there were mixed effects for self-reported racial group for women. CONCLUSIONS: Disability in the older population of Brazil shows familiar prevalence patterns by age and gender. Disparity in income and educational attainment in Brazil are the most important markers associated with group differences in mobility disability prevalence in old age.

Aged↗

PubMed2004

Variation in thresholds for reporting mobility disability between national population subgroups and studies.

BACKGROUND: Disability questions require older people to report difficulties with everyday activities, using broad categorical responses. Relatively little is known about population group differences in the thresholds for reporting difficulty or inability with medium-distance mobility against tested mobility-related performance. We aimed to estimate the thresholds on tested performance at which self-reports change from one category to another, across a range of sociodemographic subgroups. We also aimed to compare reported and tested performance across two national population studies. METHODS: The samples were from the third U.S. National Health and Nutrition Examination Study (NHANES III) and the Longitudinal Aging Study Amsterdam (LASA). Measures of gait speed, chair stands, and peak expiratory flow rate in both studies yielded the validated index of mobility-related physical limitations (MOBLI). Latent probit models were used to estimate cutpoints (thresholds) on the index for reporting difficulty or inability to walk a medium distance. RESULTS: Thresholds for reporting difficulty or inability were studied by age, sex, race, educational level, and income in NHANES III. In models adjusting for the other factors, performance thresholds for reporting disability categories varied by age and income. The younger elderly persons in NHANES III on average reported difficulties or inabilities only when they reached a more severe level of tested limitation compared with older old persons. A similar pattern exists for those on higher incomes. For race, differences in threshold were present only for reporting inability, but not difficulty. Significant differences in thresholds were not present between groups defined by sex or for years of education. Comparisons between the NHANES and LASA studies show that lower reported mobility difficulty or inability prevalence in the Dutch sample is attributable both to reporting at higher levels of limitation and to better functioning. CONCLUSIONS: There is evidence of differences in thresholds for reporting mobility disability, especially across age and income groups in older Americans. Further work is needed to understand the perceptual, attitudinal, or environmental factors that cause these reporting differences.

Activities of Daily Living↗