ARSACS, a spastic ataxia common in northeastern Québec, is caused by mutations in a new gene encoding an 11.5-kb ORF

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS or SACS) is an early onset neurodegenerative disease with high prevalence (carrier frequency 1/22) in the Charlevoix-Saguenay-Lac-Saint-Jean (CSLSJ) region of Quebec. We previously mapped the gene responsible for ARSACS to chromosome 13q11 and identified two ancestral haplotypes. Here we report the cloning of this gene, SACS, which encodes the protein sacsin. The ORF of SACS is 11,487 bp and is encoded by a single gigantic exon spanning 12,794 bp. This exon is the largest to be identified in any vertebrate organism. The ORF is conserved in human and mouse. The putative protein contains three large segments with sequence similarity to each other and to the predicted protein of an Arabidopsis thaliana ORF. The presence of heat-shock domains suggests a function for sacsin in chaperone-mediated protein folding. SACS is expressed in a variety of tissues, including the central nervous system. We identified two SACSmutations in ARSACS families that lead to protein truncation, consistent with haplotype analysis.

Information skills for distance learning

In spring 1997, the Education Services department at the University of North Carolina at Chapel Hill (UNC-CH) Health Sciences Library (HSL) developed six Web-based tutorials designed to teach information skills. This paper describes how the modules were created.

New approach to risk determination: development of risk profile for new falls among community-dwelling older people by use of a Genetic Algorithm Neural Network (GANN)

BACKGROUND

Falls risk in older people is multifactorial and complex. There is uncertainty about the importance of specific risk factors. Genetic algorithm neural networks (GANNs) can examine all available data and select the best nonlinear combination of variables for predicting falls. The aim of this work was to develop a risk profile for operationally defined new falls in a random sample of older people by use of a GANN approach.

METHODS

A random sample of 1042 community-dwelling people aged 65 and older, living in Nottingham, England, were interviewed at baseline (1985) and survivors reinterviewed at a 4-year follow-up (n = 690). The at-risk group (n = 435) was defined as those survivors who had not fallen in the year before the baseline interview. A GANN was used to examine all available attributes and, from these, to select the best nonlinear combination of variables that predicted those people who fell 4 years later.

RESULTS

The GANN selected a combination of 16 from a potential 253 variables and correctly predicted 35/114 new fallers (sensitivity = 31%; positive predictive value = 57%) and 295/321 nonfallers (specificity = 92%; negative predictive value = 79%); total correct = 76%. The variables selected by the GANN related to personal health, opportunity, and personal circumstances.

CONCLUSIONS

This study demonstrates the capacity of GANNs to examine all available data and then to identify the best 16 variables for predicting falls. The risk profile complements risk factors in the current literature identified by use of standard and conventional statistical methods. Additional data about environmental factors might enhance the sensitivity of the GANN approach and help identify those older people who are at risk of falling.

Validation of linkage by sampling based on environmental exposures

After detecting linkage in one sample, most researchers will attempt to validate this finding in another sample. Three strategies for validating a primary linkage were compared, with a focus on methods that might be appropriate in the presence of gene x environment interaction. First, a validation sample was collected and analyzed using the same ascertainment procedure and methods as the primary sample. Second, a sample of families with particular exposure patterns were ascertained subsequent to a significant test for heterogeneity due to the exposure in the primary sample. A third strategy ascertained by exposure status when exposure-defined subgroup tests were significant in the primary sample. The second strategy reduced the number of false positive linkage signals identified through exposure subgroup identification (i.e., the third strategy), but in this GAW11 data that contained no qualitative gene x environment interactions, it had poor sensitivity. Power to detect heterogeneity depends on the differences in risk between exposed and unexposed.

Analysis of 14 CAG repeat-containing genes in schizophrenia

Recently, it has been suggested that trinucleotide repeat-containing genes may be involved in the etiology of schizophrenia. This study was aimed at investigating putative associations between allelic variants or expansions of CAG repeat-containing genes (CAGrCG) and schizophrenia or its variability with respect to responsiveness to conventional neuroleptics. CAG repeat allelic variants of 14 expressed sequences were compared among three groups of subjects: neuroleptic-responder (R; n = 43) and neuroleptic-nonresponder (NR; n = 63) schizophrenic patients, and a control group (C; n = 122). No CAG expansions, in the range of those observed in neurodegenerative diseases, were identified in these 14 expressed sequences. The sizes of CAG repeat for the hGT1 gene were marginally different among the three groups of subjects (Kruskal-Wallis H (2, 456) = 10.48, Bonferroni corrected P = 0.047). Comparisons among the different groups indicated that neuroleptic responders have shorter alleles compared to controls (Mann-Whitney adjusted Z = -3.23, P = 0.0012). NR patients were not different from controls. These preliminary results suggest that the hGT1 gene, or a gene in its vicinity, may be involved in the etiology of schizophrenia or in modifying the disease phenotype with regard to outcome and/or neuroleptic responsiveness. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:694-699, 1999.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS): high-resolution physical and transcript map of the candidate region in chromosome region 13q11

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS or SACS) is a neurodegenerative disease frequent in northeastern Québec. In a previous study, we localized the disease gene to chromosome region 13q11 by identifying excess sharing of a marker allele in patients followed by linkage analysis and haplotyping. To create a detailed physical map of this region, we screened CEPH mega-YACs with 41 chromosome 13 sequence-tagged-sites (STSs) known to map to 13q11-q12. The YAC contig, composed of 27 clones, extends on the genetic map from D13S175 to D13S221, an estimated distance of at least 19.3 cM. A high-resolution BAC and PAC map that includes the ARSACS critical region flanked by D13S1275 and D13S292 was constructed. These YAC and BAC/PAC maps allowed the accurate placement of 29 genes and ESTs previously mapped to the proximal region of chromosome 13q. We confirmed the position of two candidate genes within the critical region and mapped the other 27 genes and ESTs to nearby intervals. Six BAC/PAC clones form a contig between D13S232 and D13S787 for sequencing within the ARSACS critical region.

Unusual cluster of mild invasive serogroup C meningococcal infection in a university college

The objective of this study was to describe the epidemiology and public health response to an apparent cluster of Neisseria meningitidis serogroup C infection in university students in a residential college. A conventional epidemiological approach was taken, supported by routine and novel diagnostic techniques. Over the two days of 21-22 August 1997, three cases of suspected meningococcal infection were notified from a residential college complex at a university campus in the Sydney metropolitan area. Neisseria meningitidis was grown from throat swabs of all three cases, and was isolated from the blood of one case only. All three isolates were typed as C:2a:P1.5,2. Seroconversion was demonstrated by a novel method in the three cases. Rifampicin was given to all identified contacts. Forty-seven days after the index case, a 19 year old female living in the same complex was diagnosed with bacterial meningitis, and identified contacts given rifampicin. When this isolate was found to be group C, it was decided to vaccinate residents of the college complex. Genotyping and serotyping (C:2a:P1.5) later revealed the fourth isolate to be distinct from isolates from Cases 1-3. In conclusion the authors note that Australia's increasing capacity to type meningococcal strains is essential to understanding the epidemiology of this disease. Furthermore, typing information is of critical importance when decisions are made regarding mass vaccination. As early antibiotic treatment may inhibit isolation of the organism, development of novel approaches to diagnosis and typing should be supported.

Evaluation of polymorphisms in the presenilin-1 gene and the butyrylcholinesterase gene as risk factors in sporadic Alzheimer's disease

The E4 allele of the apolipoprotein E gene (APOE) is a major risk factor for late-onset Alzheimer's disease (LOAD) but is neither necessary nor sufficient to cause the disease. In this study, we investigated polymorphisms in the presenilin-1 (PS-1), and butyrylcholinesterase (BChE) genes, which have been implicated as risk factors for LOAD. Our data-set comprised 177 AD and 118 control patients, all of whom had been histopathologically confirmed following autopsy. We have tested homozygosity for the PS-1 allele 1 and possession of the BChE-K variant in association with APOE epsilon4 as risk factors in LOAD. Our findings support an association between the PS-1 polymorphism and LOAD, finding homozygosity for allele 1 associated with an approximately two-fold increased risk. Our data also show that in subjects greater than 75 years of age possession of both BChE-K and APOE-epsilon4 alleles is associated with an increased risk of LOAD, whilst the risk associated with APOE-epsilon4 allele alone is not significant.

Hippocampal volume reduction in schizophrenia: effects of genetic risk and pregnancy and birth complications

BACKGROUND

Hippocampal volume reduction has been repeatedly demonstrated in schizophrenia. The relative contribution of genetic and environmental factors to this is unclear.

METHODS

To address this question, we compared volumetric measurements of the left and right hippocampus, obtained using stereological methods from brain MRI scans, from two groups of patients with schizophrenia as well as healthy controls (n = 26). Patients (n = 27) in the first group, had no family history of schizophrenia and had experienced severe pregnancy and birth complications (PBCs). The second group comprised of patients (n = 21) without a history of severe PBCs from families multiply affected with schizophrenia.

RESULTS

Reduction of the left hippocampal volume was associated with the diagnosis of schizophrenia but was present only in patients with a history of severe PBCs; in this group the smaller hippocampal volume, the earlier the onset of psychosis.

CONCLUSIONS

Our findings suggest that environmental factors, in this case severe PBCs, make a significant contribution to hippocampal abnormalities in schizophrenia.

Mutations in ABC1 in Tangier disease and familial high-density lipoprotein deficiency

Genes have a major role in the control of high-density lipoprotein (HDL) cholesterol (HDL-C) levels. Here we have identified two Tangier disease (TD) families, confirmed 9q31 linkage and refined the disease locus to a limited genomic region containing the gene encoding the ATP-binding cassette transporter (ABC1). Familial HDL deficiency (FHA) is a more frequent cause of low HDL levels. On the basis of independent linkage and meiotic recombinants, we localized the FHA locus to the same genomic region as the TD locus. Mutations in ABC1 were detected in both TD and FHA, indicating that TD and FHA are allelic. This indicates that the protein encoded by ABC1 is a key gatekeeper influencing intracellular cholesterol transport, hence we have named it cholesterol efflux regulatory protein (CERP).

Exclusion of linkage of Shwachman-Diamond syndrome to chromosome regions 6q and 12q implicated by a de novo translocation

Shwachman-Diamond syndrome is a rare genetic disorder of unknown pathogenesis involving exocrine pancreatic insufficiency and hematological and skeletal abnormalities. There is broad clinical variability; the extent of heterogeneity is unknown but comparisons within a large cohort of patients show no striking differences between patients of families with single or multiple affected offspring. Segregation analysis of a cohort of 69 families has suggested an autosomal recessive mode of inheritance. A single constitutional de novo chromosome rearrangement was reported in a Japanese patient involving a balanced translocation, t(6;12)(q16.2;q21.2), thereby suggesting possible loci for a genetic defect. Evenly spaced microsatellite markers spanning 26-32 cM intervals from D6S1056 to D6S304 and D12S375 to D12S346 were analyzed for linkage in members of 13 Shwachman-Diamond syndrome families with two or three affected children. Two-point lod scores were calculated for each marker under assumptions of recessive inheritance and complete penetrance. Negative lod scores indicated exclusion of both chromosome regions. Further, affected sibs were discordant for inheritance of chromosomes in most families based on constructed haplotypes. The cytogenetic abnormality is not associated with most cases of Shwachman-Diamond syndrome.

A PC12 variant lacking regulated secretory organelles: aberrant protein targeting and evidence for a factor inhibiting neuroendocrine gene expression

A variant of the PC12 pheochromocytoma cell line (termed A35C) has been isolated that lacks regulated secretory organelles and several constituent proteins. Northern and Southern blot analyses suggested a block at the transcriptional level. The proprotein-converting enzyme carboxypeptidase H was synthesised in the A35C cell line but was secreted by the constitutive pathway. Transient transfection of A35C cells with cDNAs encoding the regulated secretory proteins dopamine beta-hydroxylase and synaptotagmin I resulted in distinct patterns of mistargeting of these proteins. It is surprising that hybrid cells created by fusing normal PC12 cells with A35C cells exhibited the variant phenotype, suggesting that A35C cells express an inhibitory factor that represses neuroendocrine-specific gene expression.

Sweat production and localisation of carbonic anhydrase in the equine sweat gland during exercise at two ambient temperatures

The aim of this investigation was to study sweat production during exercise at 2 ambient temperatures (20 degrees C and 35 degrees C) and the concurrent localisation of carbonic anhydrase (CA) in the sweat gland. Horses develop alkalosis during prolonged exercise and the sweat contains HCO3-. Carbonic anhydrase is therefore of interest since it catalyses the reaction CO2 + H2O<-->HCO3- + H+. Four standardbred trotters performed an exercise test. Skin biopsies were taken from the neck, and sweat rate, blood and skin temperatures were measured. There was a close relationship between sweat rate, temperatures and work intensity at 20 degrees C. Temperatures and sweat rate were higher at 35 degrees C and did not fall when the work intensity dropped. A significant decrease in the sweat gland cell area was found after exercise at 35 degrees C with an accompanying decrease of vesicles. Strong CA activity was present at the luminal cell membrane and weaker basolaterally. The staining intensity increased after exercise. We suggest that CA might be of importance for counteracting the alkalosis developed after exercise by delivering HCO3- for generation of the alkaline pH in sweat.

The maternal DDK syndrome phenotype is determined by modifier genes that are not linked to Om

The DDK syndrome is a polar, early embryonic lethal phenotype caused by incompatibility between a maternal factor of DDK origin and a paternal gene of non-DDK origin. Both maternal factor and paternal gene have been mapped to the Om locus on mouse Chromosome (Chr) 11. The paternal contribution to the syndrome has been shown to segregate as a single locus. Although the inheritance of the maternal contribution has not been characterized in depth, it as been assumed to segregate as a single locus. We have now characterized the segregation of the DDK fertility phenotype in over 240 females. Our results demonstrate that females require at least one DDK allele at Om to manifest the syndrome. However, the DDK syndrome inter-strain cross-fertility phenotype of heterozygous females is highly variable and spans the gamut from completely infertile to completely fertile. Our results indicate that this phenotypic variability has a genetic basis and that the modifiers of the DDK syndrome segregate independently of Om.

A pilot study of melphalan, tumor necrosis factor-alpha and 41.8 degrees C whole-body hyperthermia

PURPOSE

To evaluate the feasibilitv of sequencing (based on preclinical modeling) tumor necrosis factor-a (TNF) at two dose levels with melphalan (L-PAM) and 41.8 C whole-body hyperthermia (WBH) for 60 min.

PATIENTS AND METHODS

Nine patients with refractory cancer were treated from October 1995 to June 1997. The study encompassed a total of 20 trimodality treatment courses. Three patients were treated at TNF dose level I (50 microg/m2) and six patients were treated at TNF dose level II (100 microg/m2). TNF was delivered as a 24-h intravenous infusion, 48 h prior to the combination of L-PAM and WBH; L-PAM was given over 10 min at target temperature at a dose of 17.5 mg/ m2 based on a previous phase I WBH/L-PAM trial. WBH was administered with an Aquatherm radiant heat device.

RESULTS

Myelosuppression was the major toxicity associated with therapy, but there were no instances of bleeding or neutropenic fevers. Grade 3 thrombocytopenia was seen with 15% of treatments. Regarding absolute neutrophil count, 15% of treatments were associated with grade 3 toxicity, and 45% with grade 4 toxicity, and regarding white blood cell count, 50% of treatments were associated with grade 3 toxicity and 10% with grade 4 toxicity. The myelosuppression observed was equivalent to that seen in our earlier phase I study of WBH and L-PAM (without TNF). Only mild toxicities (grade 1 or 2) were associated with TNF; these were seen with <25% of treatments and included nausea, vomiting, diarrhea, fevers, and headache. There were no instances of hypotension. There was no relationship between toxicities observed and the two TNF dose levels. Mild WBH toxicities were seen with less than 15% of treatments; these included nausea, vomiting, and herpes simplex I. Responses included two complete remissions (malignant melanoma, TNF dose level I; breast cancer, TNF dose level II), and two disease stabilizations (both malignant melanoma, TNF dose level I).

CONCLUSION

We conclude that the combination of TNF, L-PAM, and WBH is well tolerated at the dose levels studied. The clinical results justify further clinical investigation for this trimodality treatment approach.

Location score and haplotype analyses of the locus for autosomal recessive spastic ataxia of Charlevoix-Saguenay, in chromosome region 13q11

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a clinically homogeneous form of early-onset familial spastic ataxia with prominent myelinated retinal nerve fibers. More than 300 patients have been identified, and most of their families originated in the Charlevoix-Saguenay region of northeastern Quebec, where the carrier prevalence has been estimated to be 1/22. Consistent with the hypothesis of a founder effect, we observed excess shared homozygosity at 13q11, among patients in a genomewide scan of 12 families. Analysis of 19 pedigrees demonstrated very tight linkage between the ARSACS locus and an intragenic polymorphism of the gamma-sarcoglycan (SGCG) gene, but genomic DNA sequence analysis of all eight exons of SGCG revealed no disease-causing mutation. On the basis of haplotypes composed of seven marker loci that spanned 11.1 cM, the most likely position of the ARSACS locus was 0.42 cM distal to the SGCG polymorphism. Two groups of ARSACS-associated haplotypes were identified: a large group that carries a common SGCG allele and a small group that carries a rare SGCG allele. The haplotype groups do not appear to be closely related. Therefore, although chromosomes within each haplotype group may harbor a single ARSACS mutation identical by descent, the two mutations could have independent origins.

Differential risk factor profiles for indoor and outdoor falls in older people living at home in Nottingham, UK

The objectives of this work were: to estimate the incidence of falls within an at-risk group of community-dwelling elderly people; to assess the risk factors associated with incident falls; to examine the effects of incident falls on survival. A random sample of 1042 community-dwelling older people in Nottingham (UK) were interviewed in 1985 and survivors re-interviewed at 4-year follow-up. The at-risk group was defined as survivors who had not fallen in the year prior to the baseline interview (n = 444). One-year fall recall was assessed using a questionnaire and included physical health, mobility, prescribed drugs and time spent walking. Body-weight and handgrip strength were measured. Eight-year post-fall mortality was recorded. In 1989 117 new fallers were identified. These people fell a total of 233 times in the year prior to re-interview (incidence rate: 524.8 per 1000 person-years at risk; 95% confidence intervals (CI): 473.3-576.3). People aged less than 75 were more likely to fall outdoors than people aged 75 and over (chi2 = 5.715, df = 1, p = 0.017). Risk factors associated with falling were: being less healthy (odds ratio (OR): 0.55; p = 0.052); having a walking speed in the range stroll/very slow/nonambulant compared with normal/brisk/fast (OR: 1.99; p<0.01); and number of prescribed drugs (OR: 1.30; p = 0.01). When analysed separately, indoor and outdoor falls presented differential risk profiles, with evidence that indoor falls were associated with frailty, while outdoor falls were associated with compromised health status in more active people. In 8-year post-fall monitoring, multiple (3+) fallers and indoor fallers showed a significant excess mortality. The differences in risk factors for, and prognoses following, indoor and outdoor falls, emphasise the complex interactions between intrinsic and extrinsic factors associated with falling among older people.

Expression of functional angiotensin-converting enzyme and AT1 receptors in cultured human cardiac fibroblasts

BACKGROUND

Angiotensin II (Ang II) has been implicated in the development of cardiac fibrosis. The aims of the present study were to examine expression and activity of ACE and of angiotensin receptors in human cardiac fibroblasts cultured from dilated cardiomyopathic and ischemic hearts. The effects of Ang II on fibroblasts were also investigated.

METHODS AND RESULTS

Human cardiac fibroblasts were cultured from ventricular and atrial myocardium and characterized immunohistochemically. Expression of ACE and the angiotensin AT1 receptor was demonstrated in cardiac fibroblasts by reverse transcriptase-polymerase chain reaction and radioligand binding. Functional ACE activity, measured by radiolabeled substrate conversion assay, was detected in both ventricular (Vmax. Km-1. mg-1, 0.031+/-0.010; n=13) and atrial (0. 034+/-0.012; n=6) fibroblasts. Fibroblast ACE activity was increased after 48 hours of treatment with basic fibroblast growth factor, dexamethasone, and phorbol ester. Ang II did not affect DNA synthesis but stimulated [3H]proline incorporation in cardiac fibroblasts (20.0+/-4.0% increase above control by 10 micromol/L; P<0.05, n=7), which was abolished by losartan 10 micromol/L but not PD123319 1 micromol/L. Ang II also stimulated a rise in intracellular calcium (basal, 56+/-1 nmol/L; Ang II, 355+/-24 nmol/L) via the AT1 receptor, as shown by complete inhibition with losartan.

CONCLUSIONS

We have demonstrated expression and activity of ACE and AT1 receptor in cultured human cardiac fibroblasts. In addition, cardiac fibroblasts respond to Ang II with AT1 receptor-mediated collagen synthesis. The presence of local ACE and AT1 receptors in human fibroblasts suggests their involvement in the development of cardiac fibrosis.

Genetic risk factors in Alzheimer's disease

Following a brief introduction and discussion of the pathological features of Alzheimer's disease, the main emphasis of this review article will be the genetic factors that have been implicated in this disease. These can be divided into two main categories. First, the three genes in which mutations are known to result in early onset autosomal dominant familial Alzheimer's disease will be discussed. These are well characterised but account for only a small proportion of Alzheimer's disease cases. Late onset, sporadic Alzheimer's disease is more common and evidence suggests that there is a genetic component to this type of disease. A number of genetic risk factors have been implicated that might increase the risk of developing sporadic disease. Many of these are controversial and studies have shown conflicting results, which are discussed in this section. Finally, a brief discussion of some of the mechanisms suggested to play a role in the pathogenesis of Alzheimer's disease is included. It is hoped that this will show why particular genes have been implicated in Alzheimer's disease and how they might be able to influence the development of the disease.

Stability and change in levels of habitual physical activity in later life

OBJECTIVES

to describe stability and change in levels of customary physical activity assessed in recall-based questionnaire surveys of older people conducted in 1985, 1989 and 1993.

DESIGN

longitudinal study.

SUBJECTS

1042 people originally aged 65 and over randomly sampled from general practitioner lists in Nottingham, UK.

METHODS

logistic and multiple regression analyses, intraclass correlation coefficients.

MAIN OUTCOME MEASURES

self-reported time spent per day walking and shopping; self-reported time spent per week in other indoor, outdoor and leisure activities; frequency of performance of strength and flexibility activities.

RESULTS

among survivors, activity levels at baseline tended to be higher than those of their non-surviving peers. Overall, 8-year change between 1985 and 1993 was characterized by progressively declining activity levels. Nevertheless, in both trajectories and stability profiles, differences did emerge among the seven activity categories studied. At least one in four respondents increased the time they spent walking, and approximately one in three respondents increased the time they spent shopping between 1985 and 1993.

CONCLUSIONS

these findings suggest that, while some activity variables show levels of stability consistent with trait-like constructs, others are clearly more labile. While the present data cannot offer a definitive explanation for these differences, it seems reasonable that within each activity the influence of ability, opportunity and need interact to determine levels of participation.

Customary physical activity and physical health outcomes in later life

OBJECTIVES

to explore associations between customary physical activity and three longitudinal outcomes: 12-year all-cause mortality, 12-year disease-specific mortality and 8-year change in general practitioner and personal social service use.

DESIGN

longitudinal study.

SUBJECTS

1042 people originally aged 65 and over randomly sampled from general practitioner lists in Nottingham, UK.

METHODS

Cox regression survival and logistic regression analyses.

MAIN OUTCOME MEASURES

questionnaire-assessed levels of physical activity; 12-year mortality; reported health and personal social service contacts in month prior to interview.

RESULTS

on the basis of factor scores derived from the interview questionnaire, activity levels were graded as high, intermediate or low, with respondents grouped accordingly. Relative to the high activity group, 12-year mortality was significantly increased in both the intermediate [adjusted hazard ratio (HR) = 1.53; 95% confidence interval (CI) = 1.10-2.14; P < 0.05] and low (HR = 1.75; 95% CI = 1.24-2.48; P < 0.005) activity groups for men, and in the low activity group (HR= 1.73; 95% CI = 1.28-2.33; P < 0.001) for women. Lower levels of activity were also associated with an increased likelihood of using health and personal social services 8 years after the initial interview, and an increased risk among men of having respiratory disease recorded as the primary cause of death. All models were adjusted for age, health and smoking status and weight category as measured at baseline.

CONCLUSIONS

the results are consistent with the conclusion that, among elderly people, health gain resulting from higher customary physical activity levels can promote a longer and more independent later life.

Customary physical activity and psychological wellbeing: a longitudinal study

OBJECTIVES

to assess longitudinal relationships between habitual levels of physical activity and indices of psychological wellbeing in older people.

DESIGN

baseline assessment with 4- and 8-year follow-ups.

SUBJECTS

1042 people originally aged 65 and over randomly sampled from general practitioner lists in Nottingham, UK.

METHODS

logistic regression analysis of selected T1 (1985) and T2 (1989) variables, with depression at T2 as dependent; multiple regression analyses of selected T1, T2 and T3 (1993) variables, with life satisfaction at T2 (model 1) or T3 (model 2) as dependent.

MAIN OUTCOME MEASURES

questionnaire-assessed levels of physical activity; 14-item Symptoms of Anxiety and Depression scale; 13-item Life Satisfaction Index; health, demographic and social activity variables.

RESULTS

in the logistic regression model, depression at T2 was most strongly associated with depression [odds ratio (OR) = 7.13; 95% confidence interval (CI) = 3.25-15.64; P < 0.001] and lower physical health status (OR = 1.26 per unit change in score; 95% CI = 1.17-1.42; P < 0.001) at T1. Lower levels of outdoor/leisure activities at T1 were also associated with some increased risk of depression 4 years later (OR = 0.92 per hour of activity; 95% CI = 0.85-0.99; P < 0.05). Similar predictive patterns emerged from the multiple regression analyses where, in both models, earlier levels of life satisfaction, social engagement and health accounted for most of the explained variance in life satisfaction (R2 = 0.42 for model 1; R2 = 0.35 for model 2). Again, however, earlier levels of physical activity (as walking and housework) did contribute significantly, although modestly, to longitudinal changes in morale.

CONCLUSIONS

while the results provide some support for the conclusion that physical activity contributes independently to the promotion and maintenance of psychological wellbeing in later life, this contribution is, at best, extremely modest.