Randomised controlled trial of a short course of traditional acupuncture compared with usual care for persistent non-specific low back pain

OBJECTIVE

To determine whether a short course of traditional acupuncture improves longer term outcomes for patients with persistent non-specific low back pain in primary care.

DESIGN

Pragmatic, open, randomised controlled trial.

SETTING

Three private acupuncture clinics and 18 general practices in York, England.

PARTICIPANTS

241 adults aged 18-65 with non-specific low back pain of 4-52 weeks' duration.

INTERVENTIONS

10 individualised acupuncture treatments from one of six qualified acupuncturists (160 patients) or usual care only (81 patients).

MAIN OUTCOME MEASURES

The primary outcome was SF-36 bodily pain, measured at 12 and 24 months. Other outcomes included reported use of analgesics, scores on the Oswestry pain disability index, safety, and patient satisfaction.

RESULTS

39 general practitioners referred 289 patients of whom 241 were randomised. At 12 months average SF-36 pain scores increased by 33.2 to 64.0 in the acupuncture group and by 27.9 to 58.3 in the control group. Adjusting for baseline score and for any clustering by acupuncturist, the estimated intervention effect was 5.6 points (95% confidence interval -0.2 to 11.4) at 12 months (n = 213) and 8.0 points (2.8 to 13.2) at 24 months (n = 182). The magnitude of the difference between the groups was about 10%-15% of the final pain score in the control group. Functional disability was not improved. No serious or life threatening events were reported.

CONCLUSIONS

Weak evidence was found of an effect of acupuncture on persistent non-specific low back pain at 12 months, but stronger evidence of a small benefit at 24 months. Referral to a qualified traditional acupuncturist for a short course of treatment seems safe and acceptable to patients with low back pain.

TRIAL REGISTRATION

ISRCTN80764175 [controlled-trials.com].

Applications for protein sequence-function evolution data: mRNA/protein expression analysis and coding SNP scoring tools

The vast amount of protein sequence data now available, together with accumulating experimental knowledge of protein function, enables modeling of protein sequence and function evolution. The PANTHER database was designed to model evolutionary sequence–function relationships on a large scale. There are a number of applications for these data, and we have implemented web services that address three of them. The first is a protein classification service. Proteins can be classified, using only their amino acid sequences, to evolutionary groups at both the family and subfamily levels. Specific subfamilies, and often families, are further classified when possible according to their functions, including molecular function and the biological processes and pathways they participate in. The second application, then, is an expression data analysis service, where functional classification information can help find biological patterns in the data obtained from genome-wide experiments. The third application is a coding single-nucleotide polymorphism scoring service. In this case, information about evolutionarily related proteins is used to assess the likelihood of a deleterious effect on protein function arising from a single substitution at a specific amino acid position in the protein. All three web services are available at .

Challenge with mammary tumor cells expressing MHC class II and CD80 prevents the development of spontaneously arising tumors in MMTV-neu transgenic mice

The HER-2/Neu oncogene has been implicated in human and mouse breast cancer. Indeed, transgenic MMTV-neu mice expressing this oncogene from the mammary tumor virus long terminal repeat develop spontaneous mammary tumors and die within 1 year of life. We have expressed the class II transactivator (CIITA) and/or the costimulatory molecule CD80 (B7.1) in a mammary carcinoma cell line (MCNeuA) derived from these mice. Class II transactivator directs the expression of MHC class II and the machinery for antigen processing and presentation by this pathway. When injected into MMTV-neu mice, tumor cells expressing CD80 or CD80 and CIITA, were rejected completely. In addition, following the rejection of dual expressing cells, 75% of the mice were protected against the development of subsequent spontaneous tumors. Cells expressing only CD80 or CIITA were not as effective as antitumor vaccines in preventing the development of spontaneous tumors. Thus, converting cancer cells into antigen presenting cells could represent an effective immunotherapy for breast cancer.

Health Related Quality of Life in Malaysian children with thalassaemia

Background

Health Related Quality of Life (HRQoL) studies on children with chronic illness such as thalassaemia are limited. We conducted the first study to investigate if children with thalassaemia have a lower quality of life in the four dimensions as measured using the PedsQL 4.0 generic Scale Score: physical, emotional, social and role (school) functioning compared to the healthy controls allowing for age, gender, ethnicity and household income.

Methods

The PedsQL 4.0 was administered to children receiving blood transfusions and treatments at Hospital Kuala Lumpur, Malaysia using PedsQL 4.0 generic Scale Score. Accordingly, the questionnaire was also administered to a control group of healthy school children. Socio-demographic data were also collected from patients and controls using an interview schedule designed for the study.

Results

Of the 96 thalassaemia patients approached, 78 gave consent to be interviewed giving a response rate of 81.3%. Out of 235 healthy controls approached, all agreed to participate giving a response rate of 100%. The mean age for the patients and schoolchildren is 11.9 and 13.2 years respectively. The age range for the patients and the schoolchildren is between 5 to 18 years and 7 to 18 years respectively. After controlling for age and demographic background, the thalassaemia patients reported having significantly lower quality of life than the healthy controls.

Conclusion

Thalassaemia has a negative impact on perceived physical, emotional, social and school functioning in thalassaemia patients which was also found to be worse than the children's healthy counterparts. Continuing support of free desferal from the Ministry of Health should be given to these patients. More understanding and support especially from health authorities, school authorities and the society is essential to enhance their quality of life.

Language ability after early detection of permanent childhood hearing impairment

BACKGROUND

Children with bilateral permanent hearing impairment often have impaired language and speech abilities. However, the effects of universal newborn screening for permanent bilateral childhood hearing impairment and the effects of confirmation of hearing impairment by nine months of age on subsequent verbal abilities are uncertain.

METHODS

We studied 120 children with bilateral permanent hearing impairment identified from a large birth cohort in southern England, at a mean of 7.9 years of age. Of the 120 children, 61 were born during periods with universal newborn screening and 57 had hearing impairment that was confirmed by nine months of age. The primary outcomes were language as compared with nonverbal ability and speech expressed as z scores (the number of standard deviations by which the score differed from the mean score among 63 age-matched children with normal hearing), adjusted for the severity of the hearing impairment and for maternal education.

RESULTS

Confirmation of hearing impairment by nine months of age was associated with higher adjusted mean z scores for language as compared with nonverbal ability (adjusted mean difference for receptive language, 0.82; 95 percent confidence interval, 0.31 to 1.33; and adjusted mean difference for expressive language, 0.70; 95 percent confidence interval, 0.13 to 1.26). Birth during periods with universal newborn screening was also associated with higher adjusted z scores for receptive language as compared with nonverbal ability (adjusted mean difference, 0.60; 95 percent confidence interval, 0.07 to 1.13), although the z scores for expressive language as compared with nonverbal ability were not significantly higher. Speech scores did not differ significantly between those who were exposed to newborn screening or early confirmation and those who were not.

CONCLUSIONS

Early detection of childhood hearing impairment was associated with higher scores for language but not for speech in midchildhood.

Diarylureas are small-molecule inhibitors of insulin-like growth factor I receptor signaling and breast cancer cell growth

In breast and certain other cancers, receptor tyrosine kinases, including the insulin-like growth factor I receptor (IGF-IR), play an important role in promoting the oncogenic process. The IGF-IR is therefore an important target for developing new anti-breast cancer therapies. An initial screening of a chemical library against the IGF-IR in breast cancer cells identified a diaryl urea compound as a potent inhibitor of IGF-IR signaling. This class of compounds has not been studied as inhibitors of the IGF-IR. We studied the effectiveness of one diaryl urea compound, PQ401, at antagonizing IGF-IR signaling and inhibiting breast cancer cell growth in culture and in vivo. PQ401 inhibited autophosphorylation of the IGF-IR in cultured human MCF-7 cells with an IC50 of 12 micromol/L and autophosphorylation of the isolated kinase domain of the IGF-IR with an IC50 <1 micromol/L. In addition, PQ401 inhibited the growth of cultured breast cancer cells in serum at 10 micromol/L. PQ401 was even more effective at inhibiting IGF-I-stimulated growth of MCF-7 cells (IC50, 6 micromol/L). Treatment of MCF-7 cells with PQ401 was associated with a decrease in IGF-I-mediated signaling through the Akt antiapoptotic pathway. Twenty-four hours of treatment with 15 micromol/L PQ401 induced caspase-mediated apoptosis. In vivo, treatment with PQ401 (i.p. injection thrice a week) reduced the growth rate of MCNeuA cells implanted into mice. These studies indicate that diaryl urea compounds are potential new agents to test in the treatment of breast and other IGF-I-sensitive cancers.

The Effect of Helium and Oxygen on Exercise Performance in Chronic Obstructive Pulmonary Disease

RATIONALE

Breathing supplemental oxygen reduces breathlessness during exercise in patients with chronic obstructive pulmonary disease (COPD). Replacing nitrogen with helium reduces expiratory flow resistance and may improve lung emptying. Combining these treatments should be independently effective.

OBJECTIVES

Study the effect of changing oxygen or helium concentration in inspired gas during exercise in patients with stable COPD.

METHODS

In 82 patients (mean age, 69.7 yr; mean FEV(1), 42.6% predicted), we measured endurance shuttle walking distance, resting and exercise oxygen saturation, and end-exercise dyspnea (Borg scale) while patients breathed Heliox28 (72% He/28% O(2)), Heliox21 (79% He/21% O(2)), Oxygen28 (72% N(2)/28% O(2)), or medical air (79% N(2)/21% O(2)). Gases were administered using a randomized, blinded, crossover design via a face mask and an inspiratory demand valve.

RESULTS

Breathing Heliox28 increased walking distance (mean+/-SD, 147+/-150 m) and reduced Borg score (-1.28+/-1.30) more than any other gas mixture. Heliox21 significantly increased walking distance (99+/-101 m) and reduced dyspnea (Borg score, -0.76+/-0.77) compared with medical air. These changes were similar to those breathing Oxygen28. The effects of helium and oxygen in Heliox28 were independent. The increase in walking distance while breathing Heliox28 was inversely related to baseline FEV(1) breathing air.

CONCLUSION

Reducing inspired gas density can improve exercise performance in COPD as much as increasing inspired oxygen. These effects can be combined as Heliox28 and are most evident in patients with more severe airflow obstruction.

A protocol for investigation of the effects of outdoor air pollution on stroke incidence, phenotypes and survival using the South London Stroke Register

Stroke is a major cause of death and disability. About 5.3 million people die every year from stroke worldwide with over 9 million people surviving at any one time after suffering a stroke. About 1 in 4 men and 1 in 5 women aged 45 years will suffer a stroke if they live to their 85th year. It is estimated that by 2023 there will be an absolute increase in the number of people experiencing a first ever stroke of about 30% compared with 1983.

In the UK, stroke is the third commonest cause of death and the most common cause of adult physical disability and consumes 5% of the health and social services budget. Stroke is assuming strategic public health importance because of increased awareness in society, an ageing population and emerging new treatments. It is an NHS health service and research priority, being identified as a target in Our Healthier Nation and the NSF for Older People for prevention and risk factor control and in the NHS Plan as a disease requiring intermediate care planning and reduction in inequalities of care.

Whilst a number of risk factors for stroke are well known (e.g. increasing age, ethnicity, socioeconomic deprivation, hypertension), the potential importance of outdoor air pollution as a modifiable risk factor is much less well recognised. This is because studies to date are inconclusive or have methodological limitations. In Sheffield, we estimated that 11% of stroke deaths may be linked to current levels of outdoor air pollution and this high figure is explained by the fact that so many people are exposed to air pollution.

We plan to study the effects of outdoor air pollution on stroke using a series of epidemiological (i.e. population based) studies. The purpose of this project is:

• to examine if short term increases in pollution can trigger a stroke in susceptible individuals;

• to investigate if the occurrence of stroke is higher amongst people living in more polluted areas (which would be explained by a combination of exposure to short term increases and longer term exposure to higher pollution levels); and

• to see if people living in more polluted areas have reduced survival following their stroke.

We will use geographical information systems, robust statistical methods and powerful grid computing facilities to link and analyse the data. The datasets we will use are the South London Stroke Register database, daily monitored pollution data from national monitoring networks and modelled pollution data for London from the Greater London Authority. The South London Stroke Register records information on all patients who suffer a stroke ("incident" cases) living within a defined area. This stroke incidence dataset offers major advantages over previous studies examining the effects of pollution on hospital admissions and mortality, as not all patients with stroke are admitted or die and there may be a delay between the onset of stroke and admission or death. In addition, it contains other useful information, particularly the type of stroke people have suffered.

Air pollution is a potentially modifiable risk factor for stroke. This study will provide robust population level evidence regarding the effects of outdoor air pollution on stroke. If it confirms the link, it will suggest to policy-makers at national and international levels that targeting policy interventions at high pollution areas may be a feasible option for stroke prevention.

Hypopituitary patients prefer a touch-screen to paper quality of life questionnaire

Health Related Quality of Life questionnaires are frequently used for research, however only recently has their use been recommended in the routine clinical management of pituitary patients. Questionnaires frequently have complex scoring systems, and may be cumbersome, limiting widespread application. Touch-screen technology can overcome these limitations. We have developed a touch-screen 'Questions on Life Satisfaction-Hypopituitarism' QLS-H (Flash 5 Action script, program design by IG) questionnaire and compared its use and accuracy with a paper version questionnaire in 50 pituitary patients who were attending routine clinics. The HRQoL Z-score for the patient group was lower than the average for the normal UK population, as might be predicted for this patient group. There was no statistically significant difference between scores obtained by the touch-screen and paper questionnaires; mean (SD) Z score was -1.33 (1.4) for touch-screen and -1.26 (1.5) for paper. The touch-screen was preferred by 80% of patients, and quicker to complete (<5min). Additionally, there were significant errors in 14 (28%) of manually scored paper questionnaires.

IN CONCLUSION

Touch-screen QLS-H questionnaires have advantages over the paper version for the routine clinical assessment of patients with hypopituitarism.

Do 'food deserts' influence fruit and vegetable consumption?--A cross-sectional study

Lack of access to affordable healthy foods has been suggested to be a contributory factor to poor diet. This study investigated associations between diet and access to supermarkets, transport, fruit and vegetable price and deprivation, in a region divergent in geography and socio-economic indices. A postal survey of 1000 addresses (response rate 42%) gathered information on family demographics, supermarket and shop use, car ownership, mobility and previous day's fruit and vegetable intake. Postcode information was used to derive road travel distance to nearest supermarket and deprivation index. Fruit and vegetable prices were assessed using a shopping basket survey. Generalised linear regression models were used to ascertain predictors of fruit and vegetable intake. Male grocery shoppers ate less fruit than female grocery shoppers. Consumption of vegetables increased slightly with age. Deprivation, supermarket fruit and vegetable price, distance to nearest supermarket and potential difficulties with grocery shopping were not significantly associated with either fruit or vegetable consumption. These data suggest that the three key elements of a food desert, fruit and vegetable price, socio-economic deprivation and a lack of locally available supermarkets, were not factors influencing fruit or vegetable intake. We suggest that food policies aimed at improving diet should be orientated towards changing socio-cultural attitudes towards food.

Outdoor air pollution, mortality, and hospital admissions from coronary heart disease in Sheffield, UK: a small-area level ecological study

AIMS

To examine the hypothesis that coronary heart disease mortality and emergency hospital admission rates are higher in areas with higher outdoor air pollution levels.

METHODS AND RESULTS

Modelled nitrogen oxides (NO(x)), particulate matter (PM(10)), and carbon monoxide (CO) levels were interpolated to 1030 census enumeration districts using an ecological study design. Results, based on 6857 deaths and 11,407 admissions from 1994-98 and a population of 199,682 aged >or=45 years, were adjusted for age, sex, deprivation, and smoking prevalence. Mortality rate ratios were 1.17 (95% CI 1.06-1.29), 1.08 (95% CI 0.96-1.20), and 1.05 (95% CI 0.95-1.16) in the highest relative to the lowest NO(x), PM(10), and CO quintile categories, respectively. Corresponding admission rate ratios were 1.00 (95% CI 0.90-1.10), 1.01 (95% CI 0.90-1.14), and 0.88 (95% CI 0.79-0.98).

CONCLUSION

The results are consistent with an excess risk of coronary heart disease mortality in areas with high outdoor NO(x), a proxy for traffic-related pollution, but residual confounding cannot be ruled out. If causality were assumed, 6% of coronary heart disease deaths would have been attributable to outdoor NO(x,) and targeting pollution reduction measures at high pollution areas would be an option for coronary mortality prevention.

Universal newborn screening for permanent childhood hearing impairment: an 8-year follow-up of a controlled trial

An 8-year follow-up study of the birth cohort of babies enrolled in the Wessex controlled trial of universal newborn screening (UNS) for permanent childhood hearing impairment (PCHI) was undertaken to establish whether UNS would increase the proportion of all true cases of PCHI in children aged 7-9 years who are referred early. The proportion referred before 6 months of age increased from 11 of 35 (31%) children with true PCHI born during periods without UNS to 23 of 31 (74%) born during periods with UNS (difference 43%, 95% CI 19-60). UNS leads to early referral of PCHI.

Immune dysfunction and micrometastases in women with breast cancer

Cytokines produced by T lymphocytes are critical to the efficacy of a given immune response and dysregulation of immune responses may play a role in cancer progression. We assessed the intracellular cytokine profiles of T cells in the peripheral blood of women with breast cancer and explored the relationship of these responses with the presence of cancer in lymph nodes and bone marrow. Peripheral blood lymphocytes from 84 patients and 26 healthy volunteers were analyzed by 4-color flow cytometry for surface markers and for intracellular cytokines. Bone marrow samples from some of these patients were also collected and analyzed for the presence of epithelial cells (micrometastases) by flow cytometry. The percentages of both CD4(+) and CD8(+) cells producing type1 (IL-2, IFN-gamma or TNF-alpha) and type 2 (IL-4) were significantly lower in patients with breast cancer compared to healthy controls. These results indicate a general immune dysfunction in these patients as opposed to a shift in the balance of type1 and type2 cells. These dysregulated T cell responses did not correlate with age, stage of disease, or nodal status. However, we did observe a correlation between number of micrometastases in the bone marrow and T cell responsiveness.

Parkinson's disease protects against smoking?

Our aim was to estimate the pooled risk of current and former smoking for Parkinson’s disease (PD).We have reviewed all observational studies that evaluated the association between PD risk and smoking habit. Twenty six studies were identified: 21 case-control, 4 cohort and 1 cross-sectional. The cross-sectional study did not compare former with never smokers. These studies were carried out between 1968 and 2000.

There was an obvious protective effect of current smoking in the pooled estimate [risk estimate 0.37 (95% confidence interval 0.33 to 0.41)]. Former versus never smokers had pooled risk estimate of 0.84 (95% confidence interval 0.76 to 0.92). Current and former smoking do not, therefore, exert the same protective effect against PD so that it is unnecessary to postulate a biological mechanism through which smoking protects against PD. The results show that the reverse direction of causation is a more probable explanation, i.e. movement disorders of PD protect against smoking. Another explanation is that failure to develop strong smoking habits in early adult life might be a prodromal symptom of the disease and could perhaps be its first clinical manifestation.

Intraclass correlation coefficient and outcome prevalence are associated in clustered binary data

BACKGROUND AND OBJECTIVE

To describe the association between values for a proportion and the intraclass correlation coefficient (ICC).

METHODS

Analysis of data obtained from the General Practice Research Database (GPRD) for variation between United Kingdom general practices and results from a Health Technology Assessment (HTA) review for a range of outcomes in community and health services settings.

RESULTS

There were 188 ICCs from the GPRD, the median prevalence was 13.1% (interquartile range IQR 3.5 to 28.4%) and median ICC 0.051 (IQR 0.011 to 0.094). There were 136 ICCs from the HTA review, with median prevalence 6.5% (IQR 0.4 to 20.7%) and median ICC 0.006 (IQR 0.0003 to 0.036). There was a linear association of log ICC with log prevalence in both datasets (GPRD, regression coefficient 0.61, 95% confidence interval 0.53 to 0.69, P < 0.001; HTA, 0.91, 0.81 to 1.01, P < 0.001). When the prevalence was 1% the predicted ICC was 0.008 from the GPRD or 0.002 from the HTA, but when the prevalence was 40% the predicted ICC was 0.075 (GPRD) or 0.046 (HTA).

CONCLUSION

The prevalence of an outcome may be used to make an informed assumption about the magnitude of the intraclass correlation coefficient.

The use of bootstrap methods for estimating sample size and analysing health-related quality of life outcomes

Health-related quality of life (HRQoL) measures are increasingly used in trials as primary outcome measures. Investigators are now asking statisticians for advice on how to plan and analyse studies using such outcomes. HRQoL outcomes, like the SF-36, are usual measured on an ordinal scale, although most investigators assume that there exists an underlying continuous latent variable and that the actual measured outcomes (the ordered categories) reflect contiguous intervals along this continuum. The ordinal scaling of HRQoL measures means they tend to generate data that have discrete, bounded and skewed distributions. Thus, standard methods of analysis that assume Normality and constant variance may not be appropriate. For this reason, conventional statistical advice would suggest non-parametric methods be used to analyse HRQoL data. The bootstrap is one such computer intensive non-parametric method for estimating sample sizes and analysing data. We describe three methods of estimating sample sizes for two-group cross-sectional comparisons of HRQoL outcomes. We then compared the power of the three methods for a two-group cross-sectional study design using bootstrap simulation. The results showed that under the location shift alternative hypothesis, conventional methods of sample size estimation performed well, particularly Whitehead's method. Whitehead's method is recommended if the HRQoL outcome has a limited number of discrete values (<7) and/or the expected proportion of cases at either of the bounds is high. If a pilot data set is readily available then bootstrap simulation will provide a more accurate and reliable estimate, than conventional methods.Finally, we used the bootstrap for hypothesis testing and the estimation of standard errors and confidence intervals for parameters, in an example data set. We then compared and contrasted the bootstrap with standard methods of analysing HRQoL outcomes. In the data set studied, with the SF-36 outcome, the use of the bootstrap for estimating sample sizes and analysing HRQoL data produces results similar to conventional statistical methods. These results suggest that bootstrap methods are not more appropriate for analysing HRQoL outcome data than standard methods.

In vitro anticancer activity of twelve Chinese medicinal herbs

Aqueous extracts of 12 Chinese medicinal herbs, Anemarrhena asphodeloides, Artemisia argyi, Commiphora myrrha, Duchesnea indica, Gleditsia sinensis, Ligustrum lucidum, Rheum palmatum, Rubia cordifolia, Salvia chinensis, Scutellaria barbata, Uncaria rhychophylla and Vaccaria segetalis were evaluated for their antiproliferative activity on eight cancer cell lines as well as on normal human mammary epithelial cells. Five human and three murine cancer cell lines representing different tissues (breast, lung, pancreas and prostate) were used. All the crude aqueous extracts demonstrated growth inhibitory activity on some or all of the cancer cell lines, but only two showed activity against the normal mammary epithelial cells. Overall, the murine cell lines tended to be more sensitive to most of the extracts compared with the human cell lines. Among the human cell lines, cell type specificity was observed for two extracts. These results indicate the potential use of traditional Chinese medicinal herbs as antineoplastic agents and suggest that further studies evaluating their mechanism(s) of action and the isolation of active antitumor compounds are warranted.

The PANTHER database of protein families, subfamilies, functions and pathways

PANTHER is a large collection of protein families that have been subdivided into functionally related subfamilies, using human expertise. These subfamilies model the divergence of specific functions within protein families, allowing more accurate association with function (ontology terms and pathways), as well as inference of amino acids important for functional specificity. Hidden Markov models (HMMs) are built for each family and subfamily for classifying additional protein sequences. The latest version, 5.0, contains 6683 protein families, divided into 31,705 subfamilies, covering approximately 90% of mammalian protein-coding genes. PANTHER 5.0 includes a number of significant improvements over previous versions, most notably (i) representation of pathways (primarily signaling pathways) and association with subfamilies and individual protein sequences; (ii) an improved methodology for defining the PANTHER families and subfamilies, and for building the HMMs; (iii) resources for scoring sequences against PANTHER HMMs both over the web and locally; and (iv) a number of new web resources to facilitate analysis of large gene lists, including data generated from high-throughput expression experiments. Efforts are underway to add PANTHER to the InterPro suite of databases, and to make PANTHER consistent with the PIRSF database. PANTHER is now publicly available without restriction at http://panther.appliedbiosystems.com.

Patterns of intra-cluster correlation from primary care research to inform study design and analysis

OBJECTIVE

To provide information concerning the magnitude of the intraclass correlation coefficient (ICC) for cluster-based studies set in primary care.

STUDY DESIGN AND SETTING

Reanalysis of data from 31 cluster-based studies in primary care to estimate intraclass correlation coefficients from random effects models using maximum likelihood estimation.

RESULTS

ICCs were estimated for 1,039 variables. The median ICC was 0.010 (interquartile range [IQR] 0 to 0.032, range 0 to 0.840). After adjusting for individual- and cluster-level characteristics, the median ICC was 0.005 (IQR 0 to 0.021). A given measure showed widely varying ICC estimates in different datasets. In six datasets, the ICCs for SF-36 physical functioning scale ranged from 0.001 to 0.055 and for SF-36 general health from 0 to 0.072. In four datasets, the ICC for systolic blood pressure ranged from 0 to 0.052 and for diastolic blood pressure from 0 to 0.108.

CONCLUSION

The precise magnitude of between-cluster variation for a given measure can rarely be estimated in advance. Studies should be designed with reference to the overall distribution of ICCs and with attention to features that increase efficiency.

Outdoor air pollution and stroke in Sheffield, United Kingdom: a small-area level geographical study

BACKGROUND AND PURPOSE

Current evidence suggests that stroke mortality and hospital admissions should be higher in areas with elevated levels of outdoor air pollution because of the combined acute and chronic exposure effects of air pollution. We examined this hypothesis using a small-area level ecological correlation study.

METHODS

We used 1030 census enumeration districts as the unit of analysis and examined stroke deaths and hospital admissions from 1994 to 1998, with census denominator counts for people > or =45 years. Modeled air pollution data for particulate matter (PM10), nitrogen oxides (NO(x)), and carbon monoxide (CO) were interpolated to census enumeration districts. We adjusted for age, sex, socioeconomic deprivation, and smoking prevalence.

RESULTS

The analysis was based on 2979 deaths, 5122 admissions, and a population of 199 682. After adjustment for potential confounders, stroke mortality was 37% (95% CI, 19 to 57), 33% (95% CI, 14 to 56), and 26% (95% CI, 10 to 46) higher in the highest, relative to the lowest, NO(x), PM10, and CO quintile categories, respectively. Corresponding increases in risk for admissions were 13% (95% CI, 1 to 27), 13% (95% CI, -1 to 29), and 11% (95% CI, -1 to 25).

CONCLUSIONS

The results are consistent with an excess risk of stroke mortality and, to a lesser extent, hospital admissions in areas with high outdoor air pollution levels. If causality were assumed, 11% of stroke deaths would have been attributable to outdoor air pollution. Targeting policy interventions at high pollution areas may be a feasible option for stroke prevention.

A survey of statistics in three UK general practice journal

Background

Many medical specialities have reviewed the statistical content of their journals. To our knowledge this has not been done in general practice. Given the main role of a general practitioner as a diagnostician we thought it would be of interest to see whether the statistical methods reported reflect the diagnostic process.

Methods

Hand search of three UK journals of general practice namely the British Medical Journal (general practice section), British Journal of General Practice and Family Practice over a one-year period (1 January to 31 December 2000).

Results

A wide variety of statistical techniques were used. The most common methods included t-tests and Chi-squared tests. There were few articles reporting likelihood ratios and other useful diagnostic methods. There was evidence that the journals with the more thorough statistical review process reported a more complex and wider variety of statistical techniques.

Conclusions

The BMJ had a wider range and greater diversity of statistical methods than the other two journals. However, in all three journals there was a dearth of papers reflecting the diagnostic process. Across all three journals there were relatively few papers describing randomised controlled trials thus recognising the difficulty of implementing this design in general practice.

The use of bootstrap methods for analysing Health-Related Quality of Life outcomes (particularly the SF-36)

Health-Related Quality of Life (HRQoL) measures are becoming increasingly used in clinical trials as primary outcome measures. Investigators are now asking statisticians for advice on how to analyse studies that have used HRQoL outcomes.

HRQoL outcomes, like the SF-36, are usually measured on an ordinal scale. However, most investigators assume that there exists an underlying continuous latent variable that measures HRQoL, and that the actual measured outcomes (the ordered categories), reflect contiguous intervals along this continuum.

The ordinal scaling of HRQoL measures means they tend to generate data that have discrete, bounded and skewed distributions. Thus, standard methods of analysis such as the t-test and linear regression that assume Normality and constant variance may not be appropriate. For this reason, conventional statistical advice would suggest that non-parametric methods be used to analyse HRQoL data. The bootstrap is one such computer intensive non-parametric method for analysing data.

We used the bootstrap for hypothesis testing and the estimation of standard errors and confidence intervals for parameters, in four datasets (which illustrate the different aspects of study design). We then compared and contrasted the bootstrap with standard methods of analysing HRQoL outcomes. The standard methods included t-tests, linear regression, summary measures and General Linear Models.

Overall, in the datasets we studied, using the SF-36 outcome, bootstrap methods produce results similar to conventional statistical methods. This is likely because the t-test and linear regression are robust to the violations of assumptions that HRQoL data are likely to cause (i.e. non-Normality). While particular to our datasets, these findings are likely to generalise to other HRQoL outcomes, which have discrete, bounded and skewed distributions. Future research with other HRQoL outcome measures, interventions and populations, is required to confirm this conclusion.

Tid1, the Human Homologue of a Drosophila Tumor Suppressor, Reduces the Malignant Activity of ErbB-2 in Carcinoma Cells

The ErbB-2/HER-2 receptor tyrosine kinase is overexpressed in a wide range of solid human tumors. The ErbB-2 gene product is a transmembrane glycoprotein belonging to the epidermal growth factor receptor family, and its cytoplasmic domain is responsible for sending the mitogenic signals into cells. We discovered that this domain of ErbB-2 interacts with Tid1 protein, the human counterpart of the Drosophila tumor suppressor Tid56, whose null mutation causes lethal tumorigenesis during the larval stage. Tid1 also is known as a cochaperone of heat shock protein 70 (HSP70) and binds to HSP70 through its conserved DnaJ domain. We found that increased expression of Tid1 in human mammary carcinomas overexpressing ErbB-2 suppresses the expression level of ErbB-2 and attenuates the resultant ErbB-2-dependent oncogenic extracellular signal-regulated kinase 1/2 and big mitogen-activated protein kinase 1 signaling pathways leading to programmed cell death (PCD). A functional DnaJ domain of Tid1 also is required for its inhibition of ErbB-2 expression and the consequent PCD of carcinoma cells resulting from increased Tid1 expression. Importantly, ErbB-2-dependent tumor progression in animals is inhibited by increased expression of Tid1 in tumor cells. Collectively, these results suggest that Tid1 modulates the uncontrolled proliferation of ErbB-2-overexpressing carcinoma cells by reducing ErbB-2 expression and as a result suppresses the ErbB-2-dependent cancerous signaling and tumor progression. Moreover, the cochaperonic and regulatory functions of Tid1 on HSP70 most likely play an essential role in this antitumor function of Tid1 in carcinoma cells.

Smoking and Parkinson's disease: systematic review of prospective studies

We estimated the pooled risk of tobacco smoking for Parkinson's disease (PD). Inclusion criteria included systematic searches of MedLine, PsycLIT, Embase, Current Contents, previously published reviews, examination of cited reference sources, and personal contact and discussion with several investigators expert in the field. Published prospective studies on PD and cigarette smoking. When two or more studies were based on an identical study, the study that principally investigated the relationship or the study that was published last was used. Seven prospective studies were carried out between 1959 and 1997, of which six reported risk estimates. Four cohorts were based on standardised mortality rates, which were exclusively of male. Only one study included risk estimates for both males and females separately. The risk of ever smoker was 0.51 (95% confidence interval, 0.43 to 0.61). There was an obvious protective effect of current smoking in the pooled estimate (relative risk, 0.35; 95% CI, 0.26-0.47). Former smokers had lower risk compared with never smokers (relative risk, 0.66; 95% CI, 0.49-0.88). Although our pooled estimates show that smoking is inversely associated with the risk of PD, the four prospective studies that were based on follow-up of mortality of smokers had many limitations. Further studies evaluating the association between smoking and PD in women are strongly needed.

Combination of APACHE-II score and an obesity score (APACHE-O) for the prediction of severe acute pancreatitis

BACKGROUND

The advent of specific therapeutic or preventive treatments for severe acute pancreatitis creates a need to determine the risk of complications for each individual. Scoring systems used in acute pancreatitis identify groups of patients at risk of complications, but the pancreatitis-specific scores require 48 h of hospital admission to give full information. The APACHE-II score is useful within 24 h, but ignores simple clinical features, such as obesity, known to predict severity. The aim of this study was to evaluate a combination of the APACHE-II score with an obesity score in patients with acute pancreatitis, to predict severity using information available during the first 24 h of hospital admission.

METHODS

Data were collected prospectively from 186 consecutive patients with acute pancreatitis, to allow calculation of the APACHE-II score and body mass index (BMI). BMI was categorised as normal (score = 0), overweight (BMI 26-30: score = 1), or obese (BMI >30: score = 2). A logistic regression model was used to identify factors significantly associated with complications (Atlanta criteria; 104 complications in 60 patients).

RESULTS

Age, BMI and the acute physiology score independently predicted complications. Addition of the score for obesity to the APACHE-II score gave a composite score (APACHE-O) with greater predictive accuracy. At cut-off of >8, APACHE-O had sensitivity 82%, specificity 86%, positive predictive value 74%, negative predictive value 91% and overall accuracy 85%.

CONCLUSIONS

This study confirms that age, obesity and APACHE-II measured in the first 24 h of hospital admission can predict complications in acute pancreatitis. Combination of the APACHE-II and obesity scores by simple addition improved categorical prediction of severity (mild or severe) in patients with acute pancreatitis.

Effect of red clover-derived isoflavone supplementation on insulin-like growth factor, lipid and antioxidant status in healthy female volunteers: a pilot study

BACKGROUND

Isoflavones are estrogen-like plant compounds that may protect against cardiovascular disease and endocrine-responsive cancer. Isoflavones may, because of their ability to act as selective estrogen receptor modulators, alter insulin-like growth factor (IGF) status.

OBJECTIVE

The aim of this study was to assess the effect of 1-month isoflavone supplementation (86 mg/day red clover-derived isoflavones) on IGF status.

DESIGN AND SUBJECTS

Healthy pre- (n=16) and postmenopausal (n=7) women were invited to take part in a randomised, placebo-controlled crossover study with a minimum 2-month washout period.

RESULTS

: For premenopausal subjects, the change in IGF-1, IGF-BP1 and IGF-BP3 assessed at different points of the menstrual cycle did not differ between isoflavone and placebo phase. However, the change in IGF-1, when examined pre- and post-supplementation, was nonsignificantly reduced (P=0.06) on the isoflavone supplement compared to placebo. For postmenopausal subjects, the change in IGF-1, IGF-BP1 and IGFBP-3 concentrations over the supplementation period did not differ between isoflavone or placebo phase. Isoflavones increased HDL in postmenopausal women compared to placebo (P=0.02) but did not alter either cholesterol or triacylglycerol concentrations, and had no effect on antioxidant status.

CONCLUSIONS

This study shows that 1-month supplementation with red clover isoflavones has a positive effect on HDL cholesterol, but at most a small effect on IGF status in premenopausal and no effect in postmenopausal subjects. Further studies are required to ascertain the role these dietary compounds may have to play in breast cancer prevention.

PANTHER: a library of protein families and subfamilies indexed by function

In the genomic era, one of the fundamental goals is to characterize the function of proteins on a large scale. We describe a method, PANTHER, for relating protein sequence relationships to function relationships in a robust and accurate way. PANTHER is composed of two main components: the PANTHER library (PANTHER/LIB) and the PANTHER index (PANTHER/X). PANTHER/LIB is a collection of "books," each representing a protein family as a multiple sequence alignment, a Hidden Markov Model (HMM), and a family tree. Functional divergence within the family is represented by dividing the tree into subtrees based on shared function, and by subtree HMMs. PANTHER/X is an abbreviated ontology for summarizing and navigating molecular functions and biological processes associated with the families and subfamilies. We apply PANTHER to three areas of active research. First, we report the size and sequence diversity of the families and subfamilies, characterizing the relationship between sequence divergence and functional divergence across a wide range of protein families. Second, we use the PANTHER/X ontology to give a high-level representation of gene function across the human and mouse genomes. Third, we use the family HMMs to rank missense single nucleotide polymorphisms (SNPs), on a database-wide scale, according to their likelihood of affecting protein function.

Sensitivity analysis of common statistical models used to study the short-term effects of air pollution on health

The relationship between photochemical air pollutants (nitrogen dioxide and ozone) and emergency room admissions for asthma in Madrid (Spain) for the period 1995-1998 was analysed using the statistical models commonly used to studying the short-term effects of air pollution on health: linear and Cochrane-Orcutt regression, standard Poisson and Poisson corrected by overdispersion, Poisson autoregressive models, and generalised additive models. Linear regression models presented residual autocorrelation, Poisson regression models also showed overdispersion, and generalised additive models did not show residual autocorrelation and overdispersion was substantially reduced. Linear models provided biased estimates because our health outcome is non-normally distributed. Estimates from Poisson regression allowing for overdispersion and autocorrelation did not differ substantially from those reported by generalised additive models, which present the best model fit in terms of the absence of autocorrelation and reduction of overdispersion.

ATP-mediated conformational changes in the RecA filament

The crystal structure of the E. coli RecA protein was solved more than 10 years ago, but it has provided limited insight into the mechanism of homologous genetic recombination. Using electron microscopy, we have reconstructed five different states of RecA-DNA filaments. The C-terminal lobe of the RecA protein is modulated by the state of the distantly bound nucleotide, and this allosteric coupling can explain how mutations and truncations of this C-terminal lobe enhance RecA's activity. A model generated from these reconstructions shows that the nucleotide binding core is substantially rotated from its position in the RecA crystal filament, resulting in ATP binding between subunits. This simple rotation can explain the large cooperativity in ATP hydrolysis observed for RecA-DNA filaments.

Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo

Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content (234U, 235U, 236U, 238U, 238Pu, (239 + 240)Pu). The analyses were conducted using gamma spectrometry (235U, 238U), alpha spectrometry (238Pu, (239 + 240)Pu), inductively coupled plasma-mass spectrometry (ICP-MS) (234U, 235U, 236U, 238U) and accelerator mass spectrometry (AMS) (236U)). The results indicated that whenever the U concentration exceeded the normal environmental values (approximately 2 to 3 mg/kg) the increase was due to DU contamination. 236U was also present in the released DU at a constant ratio of 236U (mg/kg)/238U (mg/kg) = 2.6 x 10(-5), indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured 238Pu/(239 + 240)Pu, could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU).

PANTHER: a browsable database of gene products organized by biological function, using curated protein family and subfamily classification

The PANTHER database was designed for high-throughput analysis of protein sequences. One of the key features is a simplified ontology of protein function, which allows browsing of the database by biological functions. Biologist curators have associated the ontology terms with groups of protein sequences rather than individual sequences. Statistical models (Hidden Markov Models, or HMMs) are built from each of these groups. The advantage of this approach is that new sequences can be automatically classified as they become available. To ensure accurate functional classification, HMMs are constructed not only for families, but also for functionally distinct subfamilies. Multiple sequence alignments and phylogenetic trees, including curator-assigned information, are available for each family. The current version of the PANTHER database includes training sequences from all organisms in the GenBank non-redundant protein database, and the HMMs have been used to classify gene products across the entire genomes of human, and Drosophila melanogaster. The ontology terms and protein families and subfamilies, as well as Drosophila gene c;assifications, can be browsed and searched for free. Due to outstanding contractual obligations, access to human gene classifications and to protein family trees and multiple sequence alignments will temporarily require a nominal registration fee. PANTHER is publicly available on the web at http://panther.celera.com.

Antiproliferative activity of Chinese medicinal herbs on breast cancer cells in vitro

Chinese medicinal herbs are traditionally used to prevent and treat a variety of diseases, including cancer. These herbal preparations are purported to have many biological effects including direct antiproliferative effects on cancer cells, anti-mutagenic activity, and stimulatory or suppressive effects on immune responses. The present study investigates the effects of aqueous extracts from seventy-one Chinese medicinal herbs on the growth of five breast cancer cell lines (SK-BR-3, MCF7, MDA-MB-231, BT-474 and MCNeuA). Twenty-one percent (15 out of 71) of the extracts demonstrated greater than 50% growth inhibition on at least 4 of the 5 cell lines. Dose-response curves were obtained for several of the most potent crude extracts and demonstrated IC50 values ranging from < 10 micrograms/ml to > 1 mg/ml. Six of seven herbs tested induced high molecular weight DNA fragmentation, an early marker of apoptosis, while one of these also induced low molecular weight DNA fragmentation. Flow cytometric analysis of breast cancer cells exposed to one of these herbs (Rheum palmatum) suggested that it arrests cells in the G2/M phase of the cell cycle. These results indicate that many of the herbs used in traditional Chinese medicine for the treatment of cancer have significant growth inhibitory effects on breast cancer cells in vitro.

Effect on endometrium of long term treatment with continuous combined oestrogen-progestogen replacement therapy: follow up study

OBJECTIVE

To determine effects of five years of treatment with an oral continuous combined regimen of 2 mg 17beta-oestradiol and 1 mg norethisterone acetate on endometrial histology in postmenopausal women.

DESIGN

Follow up study in postmenopausal women.

SETTING

31 menopause clinics in the United Kingdom.

PARTICIPANTS

534 postmenopausal women, all with an intact uterus, who had completed nine months of treatment with oral continuous combined 2 mg 17beta-oestradiol and 1 mg norethisterone acetate agreed to take part in a long term follow up study. Women were assigned to different groups on the basis of the treatment status immediately before entering the original study: 360 women had taken sequential oestrogen-progestogen hormone replacement therapy, 164 had taken no hormone replacement therapy, and 10 had taken unopposed oestrogen therapy.

METHODS

Endometrial aspiration specimens were taken before the women started the continuous combined regimen, after 9 and 24-36 months, and at the end of the five year treatment period or on withdrawal from the study.

MAIN OUTCOME MEASURE

Results of endometrial histology.

RESULTS

The duration of treatment with continuous combined hormone replacement therapy was 4.4 (range 1.1-5.9) years. Data on endometrial specimens were available for 526 women after nine months of treatment, 465 women after 24-36 months of treatment, and 398 women who completed the five years treatment (345 women) or were withdrawn between the two latter visits for biopsies (53 women). No cases of endometrial hyperplasia or malignancy were detected at biopsy; 69% of women had an endometrium classified as atrophic or unassessable on completion of the study or withdrawal from it. Before the continuous combined therapy was started, complex hyperplasia was detected in 21 women who had taken sequential hormone replacement therapy before the study and in one who had taken unopposed oestrogen. All of these women had normal results on histological examination of endometrial tissue after nine months of treatment with continuous combined hormone replacement therapy, and hyperplasia did not recur after up to five years of treatment.

CONCLUSIONS

Long term treatment (for up to five years) with continuous combined hormone replacement therapy containing oestradiol 2 mg and norethisterone 1 mg daily was associated with neither endometrial hyperplasia nor malignancy. In women who had complex hyperplasia during previous sequential or unopposed regimens, the endometrium returned to normal during treatment with continuous combined hormone replacement therapy. These findings provide reassurance about the long term safety of this continuous combined regimen in terms of the endometrium.

In vitro isoflavone supplementation reduces hydrogen peroxide-induced DNA damage in sperm

Isoflavones are plant compounds, proposed to have health benefits in a variety of human diseases, including coronary heart disease and endocrine-responsive cancers. Their physiological effects include possible antioxidant activity, therefore suggesting a role for isoflavones in the prevention of male infertility. The aim of this study was to test the antioxidant effects of the isoflavones genistein and equol on sperm DNA integrity, assessed in vitro after hydrogen peroxide-mediated damage, using the comet assay. Pre-treatment with genistein or equol at doses of 0.01-100 micromol/l significantly protected sperm DNA against oxidative damage. Both ascorbic acid (10-600 micromol/l) and alpha-tocopherol (1-100 micromol/l) also protected. Compared with ascorbic acid and alpha-tocopherol, added at physiological concentrations, genistein was the most potent antioxidant, followed by equol, ascorbic acid, and alpha-tocopherol. Genistein and equol added in combination were more protective than when added singly. Based on these preliminary data, which are similar to those observed previously in lymphocytes, these compounds may have a role to play in antioxidant protection against male infertility.

Epithelial and fibroblast cell lines derived from a spontaneous mammary carcinoma in a MMTV/neu transgenic mouse

Female murine mammary tumor virus (MMTV)/neu transgenic mice, expressing a wild-type rat neu oncogene driven by an MMTV promoter, develop focal mammary adenocarcinomas that are pathologically very similar to human breast tumors. Two new cell lines were established from a mammary tumor that arose in a female MMTV/neu transgenic mouse. One of these lines, mammary carcinoma from Neu transgenic mouse A (MCNeuA), has an epithelial morphology, is cytokeratin positive, and expresses high levels of the neu transgene. Karyotyping and comparative genomic hybridization analyses demonstrated genomic alterations in the MCNeuA cell line. The other line, N202Fb3, has a fibroblast morphology, is cytokeratin negative, and expresses the neu transgene at a very low level. This cell line also expresses smooth muscle alpha-actin, suggesting that it is a myofibroblast line. The MCNeuA cell line is tumorigenic when injected into syngeneic MMTV/neu transgenic mice, with an in vivo doubling time of about 14 d. The rationale for establishing this tumor cell line was to provide a tumor transplantation system for rapidly assessing immunotherapeutic interventions before testing in the more cumbersome model of spontaneous tumor development in the MMTV/neu transgenic mice. Mice immunized with a Neu extracellular domain protein vaccine were protected against a subsequent inoculation of MCNeuA cells, indicating that this cell line will be useful for evaluating cancer vaccine strategies. This tumor cell line may also prove useful in studying the biological properties of the neu oncogene and its role in the malignant process. In addition, the tumor-derived fibroblast line may be useful for studying tumor-stromal cell interactions.

Diversity and dynamics of the T-cell response to MBP in DR2+ve individuals

It is generally accepted that multiple sclerosis (MS) is mediated by autoreactive T cells and that myelin basic protein (MBP) is one of the target autoantigens. The T-cell response to MBP has been analysed extensively, largely through the use of T-cell lines (TCL) and T-cell clones (TCC), and to date, three immunodominant regions (13-32, 84-103 and 144-163) have been described. However, given that TCL may represent a skewed pattern of peptide reactivity, we have developed a kinetic response assay in which the proliferation of peripheral blood mononuclear cells (PBMC) from MS patients and healthy individuals was measured directly against a panel of peptides spanning the full length of human MBP. Furthermore, PBMC from each subject were tested three times over the course of 18 months. A high proportion of MS patients exhibited a significant response to eight MBP regions (1-24, 30-54, 75-99, 90-114, 105-129, 120-144, 135-159 and 150-170). TCC were subsequently generated from MS subjects and were used to further define the epitope recognized in each case. Overall, normal individuals recognized significantly fewer peptides. In addition, we noted that the T-cell recognition of any one peptide can fluctuate, appearing at one time point, regressing, and subsequently reappearing at a later date. This study provides new insight into the recognition profile and dynamics of myelin-antigen-specific T cells in MS.

Design and analysis of trials with quality of life as an outcome: a practical guide

Health Related Quality of Life (HRQoL) measures are becoming more frequently used in clinical trials, as both primary and secondary endpoints. Investigators are now asking statisticians for advice on how to plan (e.g., sample size) and analyze studies using HRQoL measures. HRQoL measures such as the SF-36 are usually measured on an ordered categorical (ordinal) scale. In the designing stages and when analyzing, the scales are often scored and the scores treated as if they were continuous and normally distributed. However the ordinal scaling of HRQoL measures leads to problems in determining sample size, and conventional parametric methods of estimation and hypothesis testing may not be appropriate for such outcomes. We present practical guidelines for the design and analysis of trials with HRQoL measures as outcomes. We used conventional statistical methods (i.e., t-tests and multiple regression), various ordinal regression models (proportional odds, continuation ratio, polytomous and stereotype) and bootstrap methods to analyze an HRQoL dataset. To illustrate the various methods we used HRQoL data on the SF-36 Role Limitations Emotional dimension for two groups of patients with leg ulcers. The bootstrap, t-test, and multiple regression methods gave similar results. The various ordinal regression models also gave similar results. If the HRQoL measure has a large number of ordered categories, most of which are occupied, and the underlying scale really is continuous but measured imperfectly by an instrument with a limited number of discrete values, then an informal rule of thumb is that this discrete scale should be treated as continuous if it has seven or more categories and as ordinal otherwise.

[Parkinson's disease and smoking: coherence and plausibility]

INTRODUCTION

Many studies have shown that smoking is lower in patients with Parkinson s disease. However, in other investigations this was not observed. The various studies involved showed wide variation with regard to methodology, criteria for diagnosis and periods of observation and hence it is difficult to compare them.

DEVELOPMENT

The first studies published were designed to examine the effects of smoking in general and information was obtained regarding the possible disorders related to tobacco smoking according to the records of mortality, which may contain errors due to selective mortality and mistaken diagnosis. Most of the studies of cases and controls included prevalent cases which accepted the study, mainly hospital cases. Also it is probable that the prevalent cases of Parkinson s disease do not smoke because of their disorders of movement.

CONCLUSIONS

Many researchers have found important information about the pathophysiology of Parkinson s disease and its association with smoking. However, the hypothesis regarding the association between smoking and low risk of Parkinson s disease are various and independent, apart from the hypothesis of a truly biological mechanisms. Since the subject is still controversial, systematic reviews together with epidemiological and experimental studies are necessary.

Problems with the performance of the SF-36 among people with type 2 diabetes in general practice

OBJECTIVE

To validate the short form-36 (SF-36) among people with type 2 diabetes in general practice, and to make comparisons with the Audit of Diabetes Dependent Quality of Life (ADDQoL).

DESIGN

Postal survey with one reminder.

SETTING

Four general practices.

PATIENTS

One hundred and eighty-four eligible patients (30-70 years) with type 2 diabetes on 14 general practitioner lists.

MEASURES

SF-36 response rates, distribution of dimension scores and internal consistency. Median scores in relation to sociodemography and self-reported health. Comparisons with ADDQoL scores.

RESULTS

One hundred and thirty-one patients responded (71%). Distributions of SF-36 dimension scores were mostly skewed. Internal consistency and construct validity were acceptable, with predictable sociodemographic trends. People with illness related to or unrelated to diabetes scored significantly lower on most dimensions. SF-36 dimension scores correlated best with relevant diabetes-specific ADDQoL scores amongst respondents reporting no comorbidity.

CONCLUSIONS

Although valid and reliable, SF-36 scores are strongly affected by non-diabetic comorbidity in type 2 diabetes, supporting the complementary use of a diabetes-specific measure, providing information about the impact of diabetes specifically.

A review of ordinal regression models applied on health-related quality of life assessments

There has been increasing emphasis in medical research on the design and analysis of quality of life scales. Many quality of life scales are ordinal and statistical methods such as ordinal regression models have been reviewed on a number of occasions. However, when such models are applied, the way the data have been generated is often overlooked. In this paper we illustrate the use of ordinal regression models, in particular the proportional odds model, the partial proportional odds model and the stereotype model in the MRC Cognitive Function and Ageing Study (MRC CFAS). The partial proportional odds and the stereotype models are often under-utilized, perhaps due to the lack of available software. However, in this paper, analysis based on these models has been carried out using the popular statistical software package SAS and macros devised in SAS. Furthermore, bootstrapping techniques have been applied to obtain valid estimates of the standard errors of the parameters in the stereotype model. Strikingly different results were obtained using the different ordinal regression models. We conclude that the way the data have been generated is particularly important for the analysis of quality of life assessments. Different methods of generating scores yield data with different properties. It is now possible to fit a variety of ordinal regression models and so select the appropriate one that correctly models the data.