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Biomedical subjects

L Rushton

Publications and source records attributed to L Rushton.

At least 37 records · Page 2Linked to original sources
PubMed2000

Variability of diurnal changes in ambulatory blood pressure and nocturnal dipping status in untreated hypertensive and normotensive subjects.

An absent or diminished blood pressure (BP) fall during sleep (so-called "nondipping") has been associated with a higher risk of cardiovascular complications, but the long-term reproducibility of dipper status and the relationship between diurnal changes in BP and perceived sleep quality have not been previously documented in untreated hypertensive patients. Ambulatory BP (ABP) and dipping status were examined in 79 subjects (69 hypertensives and 10 normotensives) at 0, 6, and 12 months. Fifty-six percent of subjects had no change in their dipping status, the majority (53%) dipping normally on all three occasions. However, 44% of patients had variable dipping status, and normal nighttime dipping in BP was observed more often when patients perceived their sleep quality to be good during the period of ABP recording. These results highlight significant intrasubject variability in the diurnal fluctuations in ABP and dipper status, which may in part reflect day-to-day variations in sleep disturbance during ABP monitoring. Classifying hypertensive patients into dippers or nondippers on the basis of a single ABP recording is unreliable and potentially misleading.

Adult↗
PubMed2000

Patients and procedures in short-stay independent hospitals in England and Wales, 1997-1998.

BACKGROUND: Private hospitals' activities are not routinely reported, so what services they provide and for whom is not known. This study describes the clientele and case-mix of independent hospitals in England and Wales in 1997-1998. METHOD: Person, clinical and funding data were collected on samples of patients admitted to 215 of 221 independent hospitals open in 1997-1998. Sample numbers were weighted to reflect sampling duration, region, season and non-response. RESULTS: A total of 37,434 sampled records represented 828,422 admissions: 406,843 in-patients (5 per cent fewer than in 1992-1993) and 421,580 day cases (69 per cent more); 806,509 were residents of England and Wales (up 24 per cent); 16,628 came from overseas (down 20 per cent). Numbers increased in all age groups except children; 25 per cent were 65 or over (18 per cent in 1992-1993). The commonest procedures were abortion (11 per cent), endoscopy of the gastro-intestinal tract (10 per cent) or joints (5 per cent), lens operations (5 per cent), hernia repairs (3 per cent), and other common National Health Service (NHS) elective operations. The NHS funded 84,561 patients (11 per cent of the total) including 41,942 non-abortion cases (6 per cent). A total of 540,996 (76 per cent) paid through insurance; 119,101 (17 per cent) were self-funded including 30 per cent of the over-75s. Ninety-five per cent of patients went home, 0.3 per cent died and 0.2 per cent were transferred to NHS hospitals. CONCLUSIONS: Demand for short-stay independent hospital care is rising. The clientele is becoming older, and readier to pay out of pocket. Clinical activity is mainly surgical and similar to NHS elective surgical demand. One year's caseload equals 10 weeks' elective admissions to NHS hospitals, in that sense relieving the NHS. The scale of transfer to NHS hospitals (three per day) is small.

Adolescent↗
PubMed2000

Reporting of occupational and environmental research: use and misuse of statistical and epidemiological methods.

OBJECTIVES: To report some of the most serious omissions and errors which may occur in papers submitted to Occupational and Environmental Medicine, and to give guidelines on the essential components that should be included in papers reporting results from studies of occupational and environmental health. METHODS: Since 1994 Occupational and Environmental Medicine has used a panel of medical statisticians to review submitted papers which have a substantial statistical content. Although some studies may have genuine errors in their design, execution, and analysis, many of the problems identified during the reviewing process are due to inadequate and incomplete reporting of essential aspects of a study. This paper outlines some of the most important errors and omissions that may occur. Observational studies are often the preferred choice of design in occupational and environmental medicine. Some of the issues relating to design, execution, and analysis which should be considered when reporting three of the most common observational study designs, cross sectional, case-control, and cohort are described. An illustration of good reporting practice is given for each. Various mathematical modelling techniques are often used in the analysis of these studies, the reporting of which causes a major problem to some authors. Suggestions for the presentation of results from modelling are made. CONCLUSIONS: There is increasing interest in the development and application of formal "good epidemiology practices". These not only consider issues of data quality, study design, and study conduct, but through their structured approach to the documentation of the study procedures, provide the potential for more rigorous reporting of the results in the scientific literature.

Bias↗
PubMed2000

Collection of data for occupational epidemiologic research--results from a survey of European industry.

OBJECTIVES: This study was carried out to provide information on the development of recommendations for the harmonization of record collection and retention by European industry to aid future epidemiologic research. METHODS: A postal survey was carried out of 500 companies, stratified by size, in each of the 7 member states of the European Union. Three questionnaires were used respectively focusing on biographic and work history information, health records, and records containing information on exposures. Each questionnaire investigated the data items collected, the data format and location, the length of retention and factors influencing the length of retention. RESULTS: The response after 2 reminders was 39%, 42%, and 33% for the biographic, exposure, and health questionnaires, respectively. Most companies recorded surname, first names, gender, address, postal code, and date of birth, but information on children, place of birth, and nationality were less frequently recorded. Overall, 26% of the companies had an occupational health service, 56% using a contract service, but the percentages varied greatly between countries. Over 85% of the French and Spanish companies carried out routine health surveillance compared with 20% of the companies in Germany and the United Kingdom. Exposure was generally measured for noise (84%), but only 48% of the companies measured chemicals and particulates. Measurements were more common for specific locations (73%) than for particular jobs or individual workers. Approximately 70% of the records were discarded within 10 years, French companies being the most likely to retain all types of records. Legislation was cited as the strongest influence on retention policies. CONCLUSIONS: Unless both individuals and industry are made more aware of the importance of record keeping, future occupational epidemiology in Europe will remain limited.

Epidemiologic Methods↗
PubMed1999

Clinical implications of white coat hypertension: an ambulatory blood pressure monitoring study.

Within routine clinical practice, white coat hypertension (where blood pressure is persistently higher in the presence of the doctor or nurse but normal outside the medical setting) makes the diagnosis and management of hypertension difficult. There are conflicting data regarding the prevalence and significance of white coat hypertension. This study has used ambulatory blood pressure monitoring to detect the presence of white coat hypertension in 186 patients referred to an out-patient hypertension unit. The presence of white coat hypertension was defined as an average office blood pressure (measured on three occasions over a 2-month period) of >140/90 mm Hg and an ambulatory awake blood pressure < or = 136/86 mm Hg. The prevalence of white coat hypertension in those patients with borderline hypertension (diastolic blood pressure 90-99 mm Hg) and those with mild-to-moderate hypertension (diastolic blood pressure > or = 100 mm Hg) was determined. Echocardiography was used to assess left ventricular mass index in patients with and without white coat hypertension. The prevalence of white coat hypertension in the total group was 23%. However, the prevalence was higher (33%) in those patients with borderline hypertension compared to 9% of those patients with mild-to-moderate hypertension. There was a statistically significant increase in left ventricular mass index in patients with no evidence of white coat hypertension (125 gm/m2) compared to those with white coat hypertension (102 gm/m2). We conclude that, if office blood pressure is used to identify patients with hypertension who may require treatment, some patients will be incorrectly diagnosed and may be treated inappropriately. We recommend that ambulatory blood pressure monitoring is used in the routine assessment of all newly diagnosed hypertensive patients. Furthermore, we recommend echocardiography in patients with borderline hypertension as some will already have an increased left ventricular mass index.

Adolescent↗
PubMed1999

Is occupational dermatitis being taken seriously by UK industries?

Occupational dermatitis is a considerable burden but little is documented concerning industry response to this. A postal questionnaire survey of 1,100 UK companies was conducted to investigate skin care provision. The response rate was 51%. The person primarily responsible for health and safety had a professional qualification in only 34% of responding companies. In all, 75% of companies responded that they were required to conduct COSHH risk assessments and, of these, 71% mentioned skin hazards. Only 27% of companies had a skin care policy but 71% had procedures requiring glove use. Seventy-seven per cent of companies did not conduct regular skin checks. Twenty-six per cent had either been aware of a skin problem in the workforce in the last 12 months or had had to modify work practices. Improvement of skin care in UK industry could be facilitated by the establishment of a minimum recommended training qualification; assistance with compliance with COSHH legislation; and guidelines to design and implement a skin policy, provide worker protection and detect skin problems.

Cross-Sectional Studies↗
PubMed1998

Twenty-four hour ambulatory blood pressure: a sample from a normal British population.

The aims of this study were to determine 24 h blood pressure (BP) levels in a sample taken from a normal British population, and to investigate factors contributing to variation within the sample. Two hundred and eighty-two Caucasian subjects, with no known hypertension or cardiovascular disease were recruited from local light industry and a general practice population. Office and 24 h BPs were measured. The mean office BP was 120/75, ambulatory mean awake 115/72 and mean asleep 97/58 mm Hg. Males had a small but significantly higher mean office and awake BP but there were no differences in asleep BP. Multiple step-wise regression with age, gender, weight and height showed age to be the best predictor of variation in office BP and awake and asleep diastolic BP. However, age accounted for only a small amount of the variation and did not contribute towards the variation in systolic BP. The two standard deviation upper limits for this population for awake, asleep and overall BP were 136/86, 121/73 and 131/82 mm Hg, respectively. In conclusion, these data providing information on 24 h BP in a healthy British population may be of value in the clinical interpretation of 24 h ambulatory BP recordings in patients with suspected hypertension.

Adolescent↗
PubMed1998

The feasibility of conducting occupational epidemiology in the UK.

A postal survey was carried out of 1,000 UK companies to collect information about employee biographical and work history records. The overall response rate was 46%. All companies collected surname, forenames, address, date of birth and National Insurance number--information needed for cross-sectional studies. Other biographical details such as maiden name and National Health Service number were collected less often, which could increase the cost and difficulty of tracing ex-employees. Seventy per cent reported destroying their records within 10 years of an employee leaving, rising to 82% for companies with fewer than 100 employees. The destruction of employee records creates problems for historical cohort studies and case-control studies, and may hamper ex-employees trying to claim benefit for occupational-related illness. If the scope of future occupational epidemiology is to be improved, guidelines for the collection and retention of the data required must be developed and industry encouraged to participate.

Epidemiologic Studies↗
PubMed1997

Effect of long-term treatment with salmeterol on asthma control: a double blind, randomised crossover study.

OBJECTIVES: To determine the effect of adding salmeterol 50 micrograms twice daily for six months to current treatment in subjects with asthma who control their inhaled corticosteroid dose according to a management plan. DESIGN: A double blind, randomised crossover study. SETTING: Nottingham. SUBJECTS: 101 subjects with mild or moderate asthma taking at least 200 micrograms twice daily of beclomethasone dipropionate or budesonide. INTERVENTIONS: Salmeterol 50 micrograms twice daily and placebo for six months each, with a one month washout. Subjects adjusted inhaled steroid dose according to guidelines. MAIN OUTCOME MEASURE: Reduction in inhaled steroid use, exacerbations of asthma, and use of oral steroids. RESULTS: Data were available for 87 subjects. When compared with placebo salmeterol treatment was associated with a 17% reduction in inhaled steroid use (95% confidence interval 12% to 22%) with no significant difference in the number of subjects who had an exacerbation (placebo 25%, salmeterol 16%) or use of oral steroids. For secondary end points salmeterol treatment was associated with higher morning and evening peak expiratory flow and forced expiratory volume in one second; a reduction in symptoms, bronchodilator use and airway responsiveness to methacholine; and no effect on serum potassium concentration, 24 hour heart rate, or the final forced expiratory volume in one second achieved during a salbutamol dose-response study. CONCLUSIONS: In subjects who adjusted their inhaled steroid treatment according to guidelines the addition of salmeterol 50 micrograms twice daily was associated with a reduction in inhaled steroid use and improved lung function and symptom control.

Administration, Inhalation↗
PubMed1997

Comparison of the diagnosis of leukaemia from death certificates, cancer registration and histological reports - implications for occupational case-control studies.

It is essential in occupational case-control studies of rare diseases for ascertainment to be as complete as possible, together with an accurately defined diagnosis. A nested case-control study from a large cohort of UK oil distribution workers followed up since 1950 was carried out to investigate the association between leukaemia, in particular acute myeloid leukaemia, and exposure to benzene. Ninety-one cases occurring before 1993 were identified from death certificates or cancer registrations (available from 1971). Histopathology departments were contacted to obtain material that might confirm the diagnosis of leukaemia and this was received for 39 (43%) cases. The majority of the cases (88) were identified primarily from death certificates, with a cancer registration also being received for 56 (90%) of the 62 deaths occurring after 1971. Discrepancies in the diagnoses from these two sources were found for 12 cases, five being acute myeloid leukaemia. For the majority, the diagnosis on the death certificate was more specific than that on the cancer registration. Histology reports were received for nine of the discrepancies, all confirming the death certificate diagnosis. Although leukaemia appears to be regularly registered as a cancer, records may not be routinely updated when new clinical information becomes available. It is recommended that death certificates, cancer registrations and histology reports are obtained routinely by cancer registries to maximize both numbers of cases and diagnostic accuracy for epidemiological studies.

Case-Control Studies↗
PubMed1997

Lifestyle surveys--the complete answer?

STUDY OBJECTIVES: These were as follows: to study incompleteness of data, herein called item non-response, generated by a self completion questionnaire; to identify the characteristics of item non-responders and the types of questions liable to high item non-response rates; and to discuss possible reasons for item non-response. DESIGN: Item non-response patterns in 12,307 responders (62%) to a representative postal survey based on a stratified sample drawn from family health services authorities' (FHSA) registers were investigated. MAIN OUTCOME MEASURES: Data were analysed for item non-response in three groups depending on when the questionnaire was returned (wave analysis). The overall completion rate of the questionnaire was examined and the natural logarithm of the proportion of completed questions was used as an outcome variable in multiple regression analysis. Item nonresponse to key questions and questions of different types was examined. RESULTS: Wave analysis: the overall completion rate of the questionnaire was 86% in questionnaires returned before the first reminder and 83%-84% in those sent back after subsequent reminders. Overall pattern of item non-response; respondents failed to complete a mean of 15% and a median of 10% of the questionnaire. All questions in the questionnaire had some item non-response, ranging from 1% to 85%. Completion rates were associated with gender, age, indicators of lower socioeconomic status, and general health status. Individual questions: particular types of questions were liable to have higher item non-response, for example, linked binary questions. CONCLUSIONS: Item non-response in population postal surveys is likely to present problems in the interpretation of data by introducing bias additional to that of total non-response. Item non-response does not increase greatly with later returns, suggesting that the quality of data across responses generated by two reminders is similar. There are obstacles to reducing item non-response, such as respondent error or socioeconomic and health characteristics of the general population, that cannot be totally overcome. However, the evidence that individuals tend to complete only options within questions that apply to them and their positive behaviour is useful information for those designing questionnaires and interpreting survey data.

Adolescent↗
PubMed1997

A case-control study to investigate the risk of leukaemia associated with exposure to benzene in petroleum marketing and distribution workers in the United Kingdom.

OBJECTIVES: To investigate the risk of leukaemia in workers in the petroleum distribution industry who were exposed to low levels of benzene. METHODS: From the cohort of distribution workers, 91 cases were identified as having leukaemia on either a death certificate or on cancer registration. These cases were compared with controls (four per case) randomly selected from the cohort, who were from the same company as the respective case, matched for age, and alive and under follow up at the time of case occurrence. Work histories were collected for the cases and controls, together with information about the terminals at which they had worked, fuel compositions, and occupational hygiene measurements of benzene. These data were used to derive quantitative estimates of personal exposure to benzene. Odds ratios (OR) were calculated conditional on the matching, to identify those variables in the study which were associated with risk of leukaemia. Examination of the potential effects of confounding and other variables was carried out with conditional logistic regression. Analyses were carried out for all leukaemia and separately for acute lymphoblastic, chronic lymphocytic, acute myeloid and monocytic, and chronic myeloid leukaemias. RESULTS: There was no significant increase in the overall risk of all leukaemias with higher cumulative exposure to benzene or with intensity of exposure, but risk was consistently doubled in subjects employed in the industry for > 10 years. Acute lymphoblastic leukaemia tended to occur in workers employed after 1950, who started work after the age of 30, worked for a short duration, and experienced low cumulative exposure with few peaks. The ORs did not increase with increasing cumulative exposure. The risk of chronic lymphocytic leukaemia seemed to be related most closely to duration of employment and the highest risk occurred in white collar workers with long service. These workers had only background levels of benzene exposure. There was no evidence of an association of risk with any exposure variables, and no evidence of an increasing risk with increasing cumulative exposure, mean intensity, or maximum intensity of exposure. The patterns of risk for acute myeloid and monocytic leukaemia were different from those of the lymphoid subgroups, in which duration of employment was the variable most closely related to risk. Risk was increased to an OR of 2.8 (95% confidence interval (95% CI) 0.8 to 9.4) for a cumulative exposure between 4.5 and 45 ppm-years compared with < 0.45 ppm-years. For mean intensity between 0.2 and 0.4 ppm an OR of 2.8 (95% CI 0.9 to 8.5) was found compared with < 0.02 ppm. Risk did not increase with cumulative exposure, maximum intensity, or mean intensity of exposure when treated as continuous variables. Cases of acute myeloid and monocytic leukaemia were more often classified as having peaked exposures than controls, and when variables characterising peaks, particularly daily and weekly peaks, were included in the analysis these tended to dominate the other exposure variables. However, because of the small numbers it is not possible to distinguish the relative influence of peaked and unpeaked exposures on risk of acute myeloid and monocytic leukaemia. There was no evidence of an increased risk of chronic myeloid leukaemia with increases in cumulative exposure, maximum intensity, mean intensity, and duration of employment, either as continuous or categorical variables. Analyses exploring the sensitivity of the results to the source and quality of the work histories showed similar patterns in general. However, no increases in ORs for categories of cumulative exposure were found for acute myeloid and monocytic leukaemia in the data set which included work histories obtained from personnel records still in existence, although numbers were reduced. Analyses excluding the last five and 10 years of exposure showed a tendency for ORs to reduce for chronic lymphocytic leukaemia and chronic myeloid leukaemia, and to increase for acute myeloid and monocytic leukaemia. Limitations of the study include uncertainties and gaps in the information collected, and small numbers in subcategories of exposure which can lead to wide CIs around the risk estimates and poor fit of the mathematical models. CONCLUSIONS: There is no evidence in this study of an association between exposure to benzene and lymphoid leukaemia, either acute or chronic. There is some suggestion of a relation between exposure to benzene and myeloid leukaemia, in particular for acute myeloid and monocytic leukaemia. Peaked exposures seemed to be experienced for this disease. However, in view of the limitations of the study, doubt remains as to whether the risk of acute myeloid and monocytic leukaemia is increased by cumulative exposures of < 45 ppm-years. Further work is recommended to review the work histories and redefine their quality, to explore the discrepancies between results for categorical and continuous variables, and to develop ranges around the expose estimates to enable further sensitivity analyses to be carried out.

Benzene↗
PubMed1997

Retrospective estimation of exposure to benzene in a leukaemia case-control study of petroleum marketing and distribution workers in the United Kingdom.

OBJECTIVE: To provide quantitative estimates of exposure to benzene for cases and controls in an epidemiology study to investigate the risk of leukaemia in petroleum distribution workers. METHODS: Work histories were obtained for cases and controls together with detailed information on the distribution sites. For each job in the work history, an estimate of exposure (parts per million (ppm)) was obtained by multiplying a measure derived from exposure data by modifying factors to reflect the differences between the conditions that existed at the time of measurement and those at the time of interest. The modifying factors used related to job activity, the number of road tankers loaded, the benzene content of the gasoline, the mixture of products handled, temperature, and loading technology. Cumulative exposures for each case and control were obtained by multiplying the exposure estimates for each job by the duration of time in the respective jobs, and summing these over all jobs in the work history. Peak exposure and exposure through dermal contact were quantitatively classified for each job. RESULTS: Measured exposures were obtained for 30 job categories, and ranged from 0.003 to 8.20 ppm. 40% of work histories were assigned background exposures, with a further 34% assigned the exposure estimate for a driver carrying out top submerged loading of motor fuel into road tankers. Cumulative exposures ranged from < 1 to > 200 ppm-years, although 81% were < 5 ppm-years. Comparison of the exposure estimates for selected jobs with data from sources not used in the study showed similar results. CONCLUSION: The estimates of exposure to benzene in this study provide a sound basis for the epidemiological analyses.

Benzene↗
PubMed1996

Benzene exposure in the petroleum distribution industry associated with leukemia in the United Kingdom: overview of the methodology of a case-control study.

This paper describes basic principles underlying the methodology for obtaining quantitative estimates of benzene exposure in the petroleum marketing and distribution industry. Work histories for 91 cases of leukemia and 364 matched controls (4 per case) identified for a cohort of oil distribution workers up to the end of 1992 were obtained, primarily from personnel records. Information on the distribution sites, more than 90% of which were closed at the time of data collection, was obtained from site visits and archive material. Industrial hygiene measurements measured under known conditions were assembled for different tasks. These were adjusted for conditions where measured data were not available using variables known to influence exposure, such as temperature, technology, percentage of benzene in fuel handled, products handled, number of loads, and job activity. A quantitative estimate of dermal contact and peak exposure was also made.

Benzene↗
PubMed1996

Evaluation of Surgicel Nu-knit, Merocel and Vasolene gauze nasal packs: a randomized trial.

A randomised, prospective trial to evaluate Surgicel Nu-knit with Vasolene ribbon gauze and Merocel packs, respectively. Sixty patients (36 males and 24 females) undergoing bilateral nasal surgery, each having the same procedure performed on both sides, were recruited. The mean age was 49 years (range: 16-70 years). At operation, Surgicel Nu-knit was placed in one nostril, the other nostril was randomised to Vasolene gauze or Merocel. Twenty-four hours post-operatively, patients were asked to assess the discomfort experienced in either side of the nose while the packs were in position and on removal. The length of time and estimated amount of bleeding following removal of packs were also assessed. Surgicel Nu-knit caused significantly less discomfort both while in position and on removal than Vasolene gauze (p < 0.01, respectively). Compared to Merocel sponges, Surgicel Nu-knit caused significantly less discomfort on removal (p < 0.01). Bleeding following removal was also significantly less compared to the other packs. One patient in the Surgicel group required a general anaesthetic to remove a retained pack fragment. At 6-week follow-up, no nasal complications were noted in all of the groups.

Cellulose, Oxidized↗