Case-control study of hospital admission with asthma in children aged 5-14 years: relation with road traffic in north west London

BACKGROUND

Evidence for an association between road traffic pollution and asthma is inconclusive. We report a case-control study of hospital admissions for asthma and respiratory illness among children aged 5-14 in relation to proxy markers of traffic related pollution.

METHODS

The study was based on routine hospital admissions data in 1992/3 and 1993/4 for North Thames (West) health region within the M25 motorway. Cases were defined as emergency admissions for asthma (n = 1380) or all respiratory illness including asthma (n = 2131), and controls (n = 5703) were other emergency admissions excluding accidents. Cases and controls were compared with respect to distance of residence from nearest main road or roads with peak hour traffic >1000 vehicles and traffic volume within 150 m of residence, obtained by Geographical Information System techniques. Statistical analysis included adjustment for age, sex, admitting hospital, and a deprivation score for the census enumeration district of residence.

RESULTS

Adjusted odds ratios of hospital admission for asthma and respiratory illness for children living within 150 m of a main road compared with those living further away were, respectively, 0.93 (95% CI 0.82 to 1.06) and 1.02 (95% CI 0.92 to 1.14).

CONCLUSIONS

This study showed no association between risk of hospital admission for asthma or respiratory illness among children aged 5-14 and proxy markers of road traffic pollution.

Lymphohaematopoietic malignancy around all industrial complexes that include major oil refineries in Great Britain

OBJECTIVES

To examine the incidence of lymphohaematopoietic malignancy around industrial complexes that include major oil refineries in Great Britain after recent public and scientific concern of possible carcinogenic hazards of emissions from the petrochemical industry.

METHODS

Small area study of the incidence of lymphohaematopoietic malignancies, 1974-91, within 7.5 km of all 11 oil refineries (grouped into seven sites) in Great Britain that were operational by the early 1970s and processed more than two million tonnes of crude oil in 1993.

RESULTS

Combined analysis of data from all seven sites showed no significant (p < 0.05) increase in risk of these malignancies within 2 km or 7.5 km. Hodgkin's lymphoma, but no other malignancy, showed evidence (p = 0.02) of a decline in risk with distance from refineries, but there was an apparent deficit of cases of multiple myeloma near the refineries (p = 0.04).

CONCLUSION

There was no evidence of association between residence near oil refineries and leukaemias, or non-Hodgkin's lymphoma. A weak positive association was found between risk of Hodgkin's disease and proximity to major petrochemical industry, and a negative association with multiple myeloma, which may be chance findings within the context of multiple statistical testing.

How should age affect management of acute myocardial infarction? A prospective cohort study

BACKGROUND

About 75% of patients with acute myocardial infarction are older than 70 years, but patients in this age group are commonly treated less vigorously than younger patients. This differential treatment may partly reflect clinicians' misconceptions about the outlook of such patients, and the importance of age in clinical decisions. We examined how age does and should affect the management of patients and risk stratification in acute myocardial infarction.

METHODS

In this prospective cohort study, we recruited 1225 consecutive patients admitted with acute myocardial infarction to a district general hospital in east London. The primary endpoint was death. We used tabulation and regression methods to analyse the association between age group and clinical variables.

FINDINGS

Patients aged 70 years or older took a longer time to arrive in hospital and were less likely to receive thrombolysis or discharge beta-blockers than patients younger than 60 years: odds ratio 0.63 (95% CI 9.45-0.88) for thrombolysis and 0.25 (0.16-0.37) for beta-blockade, adjusted for sex, diabetes, previous acute myocardial infarction, Q wave infarction, and left-ventricular failure. Left-ventricular failure was the strongest independent predictor of death within 1 year of infarction with a hazard ratio of 4.76 (3.53-6.43), adjusted for age, sex, diabetes, and Q wave infarction. Patients aged 70 years or older without left-ventricular failure had significantly better survival at 1 year after acute myocardial infarction than patients under 60 years with left-ventricular failure. 70.8% (62.2-78.2) of the older patients who survived to hospital discharge were still alive 3 years later.

INTERPRETATION

Elderly patients with acute myocardial infarction were treated less vigorously than younger patients. The prognosis of acute myocardial infarction, however, was substantially affected by the development of left-ventricular failure and other clinical indices, such that many older patients had a better outlook than younger patients with adverse clinical factors. In planning risk-based management, consideration of age independently of clinical status is inappropriate.

Mortality among residents near cokeworks in Great Britain

OBJECTIVES

To investigate whether residents near cokeworks have a higher standardised mortality than those further away, particularly from cardiovascular and respiratory causes, which may be associated with pollution from cokeworks.

METHOD

Cross sectional small area study with routinely collected postcoded mortality data and small area census statistics. Populations within 7.5 km of 22 cokeworks in Great Britain, 1981-92. Expected numbers of deaths within 2 and 7.5 km of cokeworks, and in eight distance bands up to 7.5 km of cokeworks, were calculated by indirect standardisation from national rates stratified for age and sex and a small area deprivation index, and adjusted for region. Age groups examined were all ages, 1-14, 15-64, 65-74, > or = 75. Only the 1-14 and 15-44 age groups were examined for asthma mortality.

RESULTS

There was a 3% (95% confidence interval (95% CI) 1% to 4%) excess of all deaths within 2 km of cokeworks, and a significant decline in mortality with distance from cokeworks. The excess of deaths within 2 km was slightly higher for females and elderly people, but excesses within 2 km and declines in risk with distance were significant for all adult age groups and both sexes. The size of the excess within 2 km was 5% (95% CI 3% to 7%) for cardiovascular causes, 6% (95% CI 3% to 9%) for ischaemic heart disease, and 2% (95% CI -2% to 6%) for respiratory deaths, with significant declines in risk with distance for all these causes. There was a non-significant 15% (95% CI -1% to 101%) excess in asthma mortality in the 15-44 age group. There were no significant excesses in mortality among children but 95% CIs were wide. Within 2 km of cokeworks, the estimated additional excess all cause mortality for all ages combined related to region and mainly to the greater deprivation of the population over national levels was 12%.

CONCLUSIONS

A small excess mortality near cokeworks as found in this study is plausible in the light of current evidence about the health impact of air pollution. However, in this study the effects of pollution from cokeworks, if any, are outweighed by the effects of deprivation on weighed by the effects of deprivation on mortality near cokeworks. It is not possible to confidently exclude socioeconomic confounding or biases resulting from inexact population estimation as explanations for the excess found.

Clinical characteristics determining the mode of presentation in patients with acute coronary syndromes

OBJECTIVES

The purpose of this study was to examine clinical characteristics of patients with acute coronary syndromes to identify factors that influence the mode of presentation.

BACKGROUND

In acute coronary syndromes, presentation with myocardial infarction or unstable angina has major prognostic implications, yet clinical factors affecting the mode of presentation are not well defined.

METHODS

A prospective cohort study was made of 1,111 patients with acute coronary syndromes. Baseline demographic, clinical and biochemical data were compared in groups with myocardial infarction (n = 633) and unstable angina (n = 478).

RESULTS

The risk of myocardial infarction relative to unstable angina was increased by age >70 years (odds ratio [OR] 2.21; 95% confidence interval [CI] 1.33 to 3.66), male gender (OR 1.56; CI 1.13 to 2.16) and cigarette smoking (OR 1.49; CI 1.09 to 2.03). A rise in admission creatinine from the 10th to the 90th centile of the distribution also increased the odds of myocardial infarction (OR 1.30; CI 1.05 to 1.94). Conversely, the risk of myocardial infarction relative to unstable angina was reduced by previous treatment with aspirin (OR 0.37; CI 0.27 to 0.52), hypertension (OR 0.64; CI 0.47 to 0.86) and previous acute coronary syndromes (OR 0.36; CI 0.26 to 0.51) and revascularization procedures (OR 0.36; CI 0.21 to 0.62).

CONCLUSIONS

The clinical presentation of acute coronary syndromes may be influenced by various factors that have the potential to influence the coagulability of the blood, the collateralization of the coronary circulation and myocardial mass. Myocardial infarction is favored by cigarette smoking, advanced age and renal impairment, while unstable angina is favored by treatment with aspirin, hypertension, previous revascularization and previous coronary syndromes.

Identification of three major clones of multiply antibiotic-resistant Streptococcus pneumoniae in Taiwanese hospitals by multilocus sequence typing

In this paper we demonstrate the advantages of a new molecular typing procedure, multilocus sequence typing, for the unambiguous characterization of penicillin-resistant pneumococci. The sequences of approximately 450-bp fragments of seven housekeeping genes were determined for 74 penicillin-resistant Taiwanese isolates of Streptococcus pneumoniae (MIC of penicillin > 0.5 microgram/ml). The combination of alleles at the seven loci defined an allelic profile for each strain, and a dendrogram, based on the pairwise mismatches in allelic profiles, grouped 86% of the isolates into one of three penicillin-resistant clones for which the MICs of penicillin were 1 to 2 microgram/ml. Isolates within each clone had identical alleles at all seven loci or differed at only a single locus, and the fingerprints of their pbp1A, pbp2B, and pbp2X genes were uniform. Isolates of the Taiwan-19F clone and the Taiwan-23F clone were resistant to penicillin, tetracycline, and erythromycin but were susceptible to chloramphenicol. A second serotype 23F clone and serotype 19F variants of this clone were resistant to penicillin, tetracycline, chloramphenicol, and, in some cases, erythromycin. Comparisons of the allelic profiles of the three major clones with those of reference isolates of the known penicillin-resistant clones showed that the Taiwan-19F and Taiwan-23F clones were previously undescribed, whereas the second serotype 23F clone was indistinguishable from the Spanish multidrug-resistant serotype 23F clone. Single isolates of the Spanish penicillin-resistant serotype 9V clone and the Spanish multidrug-resistant serotype 6B clone were also identified in the collection.

Circadian activity of the endogenous fibrinolytic system in stable coronary artery disease: effects of beta-adrenoreceptor blockers and angiotensin-converting enzyme inhibitors

OBJECTIVES

To examine circadian changes in the sympathovagal balance, the activity of the renin-angiotensin system and hemostatic variables in patients with stable coronary artery disease, and the effects of beta-adrenoceptor blockade and angiotensin-converting enzyme inhibition.

BACKGROUND

Sympathovagal balance and key components of the fibrinolytic system show circadian variability. The effects of beta-adrenergic blocking agents and angiotensin-converting enzyme inhibitors on these autonomic and hemostatic rhythms are not well defined.

METHODS

Twenty patients with coronary artery disease underwent 24-h Holter monitoring for heart rate variability and blood sampling (6 hourly for 24 hours) after three consecutive treatment phases, (firstly with placebo, then bisoprolol, and finally quinapril). The effects on sympathovagal balance, hemostatic variables and the renin-angiotensin system activity were measured.

RESULTS

The fibrinolytic capacity showed marked circadian variation at the end of the placebo phase (p = 0.002), plasminogen activator inhibitor-1 (PAI-1) activity peaking at 06.00 AM when tissue plasminogen activator (tPA) activity was at its nadir. Sympathovagal balance showed a sharp increase at approximately the same time but plasma renin activity did not rise until later in the day. Inspection of the 24-h profiles suggested that bisoprolol reduced sympathovagal balance and the morning peak of PAI-1 activity and antigen, with a small increase in tPA activity, although these changes were not significant. Quinapril produced a substantial rise in renin (p = 0.01) but did not significantly affect either PAI-1 or tPA. Sympathovagal balance was unaffected by quinapril.

CONCLUSIONS

In patients with stable coronary artery disease, angiotensin-converting enzyme inhibition with quinapril does not affect either sympathovagal balance or the endogenous fibrinolytic system. Our data suggest that the sympathoadrenal system may modify fibrinolytic activity, judged by the response to beta-adrenoreceptor blockade with bisoprolol.

Frequency and prognostic implications of conduction defects in acute myocardial infarction since the introduction of thrombolytic therapy

OBJECTIVE

To document the frequency of conduction defects and their influence on prognosis in a large series of patients with acute myocardial infarction who underwent coronary care during a period when thrombolytic therapy was in common usage.

BACKGROUND

Conduction defects have been associated with an adverse prognosis following acute myocardial infarction, but there are few data on the incidence and outcome of conduction defects since the introduction of thrombolytic therapy.

PATIENTS AND METHODS

The study group comprised 1225 consecutive patients with acute myocardial infarction treated in the coronary care unit from 1 January 1988 to 31 December 1994. Conduction defects were recorded prospectively and were classified as follows: complete atrioventricular node block associated with narrow complex escape rhythms; left or right bundle branch block; bifascicular block; complete heart block involving both bundle branches.

RESULTS

Electrocardiographic data were available in 1220 patients. Complete atrioventricular node block occurred in 65 (5.3%), left and right bundle branch block in 29 (2.4%) and 44 (3.6%) bifascicular block in 36 (2.9%) and complete heart block involving both bundle branches in 20 (1.6%). The more advanced degrees of block in the bundle branches occurred more commonly in patients with diabetes, previous infarction. Q-wave infarction, anterior infarction and left ventricular failure. Survival analysis showed an increased short- and long-term cardiac mortality in patients with conduction defects, prognosis worsening as the severity of the conduction defect increased.

CONCLUSION

Conduction defects complicated acute myocardial infarction in 16% of cases and had a graded impact on the short- and long-term prognosis, patients with advanced bundle branch involvement faring worst. The data showed a small decline in the rate of severe conduction defects compared with previous studies, possibly reflecting the beneficial effects of thrombolytic therapy on infarct size.

Plasma insulin-like growth factor-I and prostate cancer risk: a prospective study

Insulin-like growth factor-I (IGF-I) is a mitogen for prostate epithelial cells. To investigate associations between plasma IGF levels and prostate cancer risk, a nested case-control study within the Physicians' Health Study was conducted on prospectively collected plasma from 152 cases and 152 controls. A strong positive association was observed between IGF-I levels and prostate cancer risk. Men in the highest quartile of IGF-I levels had a relative risk of 4.3 (95 percent confidence interval 1.8 to 10.6) compared with men in the lowest quartile. This association was independent of baseline prostate-specific antigen levels. Identification of plasma IGF-I as a predictor of prostate cancer risk may have implications for risk reduction and treatment.

Tuberculosis in health service employees in Northern Ireland

Tuberculosis can be transmitted from patients to health care workers. However, where the incidence of tuberculosis is low, and good infection control practices exist, the risk of health care workers acquiring the disease is likely to be small. The objective of this study was to determine the rate of notification of tuberculosis in health care workers in Northern Ireland compared with the general population. Information from the statutory tuberculosis notification forms for the period 1982-1991 was entered on to a computer database. Those patients involved in health care occupations were identified and age and sex standardized incidence rates were calculated. The overall notification rate for tuberculosis was 7.4 cases per 100,000 of general population. There was no significant increase in notification of tuberculosis among health care workers [standardized incidence ratio: 126% (95% CI 91-170)]. No cases were diagnosed as a result of screening methods performed during employment. It was concluded that health care workers in Northern Ireland did not have a significantly increased incidence of tuberculosis compared with the general population over the 10-year period studied. This suggests that the risk of transmission from patients to health care workers is negligible in the setting of a low general incidence of tuberculosis and good infection control practice. Under these circumstances, the present findings support the cessation of routine screening of health care workers.

Prognostic factors for patients with advanced seminoma treated with platinum-based chemotherapy

Prognostic factors for 3-year progression-free survival (PFS) were defined in 286 patients with advanced seminoma treated with cisplatin-based chemotherapy at 10 European oncology units (no prior treatment: 236; prior radiotherapy: 50). Previously irradiated patients displayed a 69% PFS as compared to 87% in those presenting with advanced seminoma at the time of diagnosis (P = 0.009). In the univariate analysis, the extent and site of disease before chemotherapy and the level of serum LDH (< 2.0 versus > or = 2.0 x upper limit of normal) correlated with PFS in previously non-irradiated patients, but not in patients with prior radiotherapy. The multivariate analysis was, therefore, restricted to previously non-irradiated patients. The presence of non-pulmonary visceral metastases and a serum LDH level of > or = 2 x normal (N) proved to be independent prognostic factors. Based on these variables, two prognostic models were constructed and validated in an external data set of 166 comparable patients. For clinical use, Model 2 is recommended. The good-prognosis group comprises non-irradiated patients with stage II seminoma and any LDH level at presentation, or stage III and IV patients (with lung metastases only) whose serum LDH level is < 2 x N. These patients display a 94% 3-year PFS. The poor prognosis group includes all other patients with a 56% PFS. With this prognostic model, individualisation of the therapeutic approach may be considered in patients with advanced seminoma and a high risk of chemotherapy-related toxicity.

Glutathione reduces the toxicity and improves quality of life of women diagnosed with ovarian cancer treated with cisplatin: results of a double-blind, randomised trial

BACKGROUND

Early clinical trials have suggested that glutathione (GSH) offers protection from the toxic effects of cisplatin.

PATIENTS AND METHODS

One hundred fifty-one patients with ovarian cancer (stage I-IV) were evaluated in a clinical trial of cisplatin (CDDP) +/- glutathione (GSH). The objective was to determine whether GSH would enhance the feasibility of giving six cycles of CDDP at 100 mg/m2 without dose reduction due to toxicity.

RESULTS

When considering the proportion of patients receiving six courses of CDDP at any dose, GSH produced a significant advantage over control--58% versus 39%, (P = 0.04). For these patients there was a significant difference between the reduction in creatinine clearance for GSH treated patients compared with control--74% versus 62% (P = 0.006). Quality of life scores demonstrated that for patients receiving GSH there was a statistically significant improvement in depression, emesis, peripheral neurotoxicity, hair loss, shortness of breath and difficulty concentrating. As an indication of overall activity, these patients were statistically significantly more able to undertake housekeeping and shopping. Clinically assessed response to treatment demonstrated a trend towards a better outcome in the GSH group (73% versus 62%) but this was not statistically significant (P = 0.25).

CONCLUSIONS

The results demonstrate that adding GSH to CDDP allows more cycles of CDDP treatment to be administered because less toxicity is observed and the patient's quality of life is improved.

Attenuation or absence of circadian and seasonal rhythms of acute myocardial infarction

OBJECTIVES

To examine the circadian, seasonal, and weekly rhythms of acute myocardial infarction, and to identify subgroups in whom the rhythms are attenuated or absent to provide further information about the mechanisms of the rhythms and the processes responsible for triggering plaque events.

DESIGN AND SETTING

Prospective, observational study in a general hospital.

PATIENTS AND METHODS

1225 consecutive patients admitted to a coronary care unit with acute myocardial infarction were studied. Admission rates were calculated according to the hour of the day (circadian rhythm), day of the week (weekly rhythm), and month of year (seasonal rhythm). The data were analysed for variations within the whole group and within subgroups.

RESULTS

A weekly rhythm of acute myocardial infarction could not be demonstrated but there was a trend towards higher admission rates at the beginning of the week. However, the time of onset of symptoms showed significant circadian variation for the group as a whole, peaking in the morning (P = 0.006), against an otherwise fairly constant background rate. Subgroup analysis showed complete absence of the circadian rhythm in patients who were diabetic, South Asian, or taking beta blockers or aspirin on admission. Significant seasonal variation in admission rates was also demonstrated for the group as a whole with a winter peak and a summer trough (P = 0.009). Again, no seasonal rhythm could be demonstrated in patients who were diabetic, South Asian, or taking beta blockers or aspirin on admission.

CONCLUSIONS

The absence of circadian and seasonal rhythms of acute myocardial infarction in almost identical subgroups suggests that common mechanisms are involved in driving these rhythms. The autonomic nervous system is a likely candidate because the rhythms were absent in patients taking beta blockers as well as in patients in whom derangement of autonomic function commonly occurs.

Cancer incidence and mortality around the Pan Britannica Industries pesticide factory, Waltham Abbey

OBJECTIVES

To examine the incidence and mortality of cancer near the Pan Britannica Industries factory, Waltham Abbey, after reports of a possible cluster of all cancers and brain cancer in the vicinity.

METHOD

Small area study of cancer incidence 1977-89, and mortality 1981-92, within a 7.5 km radius of the factory site. Postcoded cancer registrations and deaths in the study area were extracted from national data sets held by the Small Area Health Statistics Unit and compared with expected numbers computed by applying national rates stratified for age, sex, and deprivation to the local population (1981 and 1991 censuses). Observed/ expected (O/E) ratios were examined from 0-1 km and 0-7.5 km of the plant, and tests applied for a decline in relative risk with distance up to 7.5 km.

RESULTS

There were 12,859 incidence cancers (1977-89) from 0-7.5 km (O/E ratio 1.04; 95% confidence interval (95% CI) 1.02 to 1.06) and 385 from 0-1 km (O/E 1.10; 1.00 to 1.22). There was an excess of skin melanoma from 0-1 km based on 11 cases (O/E 2.13; 1.06 to 3.80), and an excess from 0-7.5 km of cancer of the lung, stomach and pancreas combined, and prostate (O/Es ranged from 1.09 to 1.13). Only the findings from lung cancer were suggestive of a decline in risk with distance, especially in the later period (1982-9). There were 9196 cancer deaths (1981-92) from 0-7.5 km (O/E 1.04; 95% CI 1.02 to 1.06) and 308 from 0-1 km (O/E 1.24; 1.11 to 1.39); and 25507 non-cancer deaths (O/E 1.02; 1.01 to 1.04) from 0-7.5 km and 745 (O/E 1.14; 1.06 to 1.22) from 0-1 km. There was evidence of a decline in mortality with distance for all cancers combined, lung cancer (P = 0.001 for each), and colorectal cancer (P < 0.05), and also for non-cancers (P = 0.001). Proportional mortality analyses suggested a decline in risk with distance for lung cancer (P = 0.003) but not for all cancers or the site specific cancers examined. There was no evidence of an excess in the incidence or mortality from brain cancer. For cancer mortality in the inner-most wards, the findings were, for the most part, well within the range of variation across the region as a whole.

CONCLUSIONS

The study provides limited and inconsistent evidence for a localised excess of cancer in the vicinity of the PBI plant. At present, further investigation does not seem warranted other than continued surveillance of mortality and cancer incidence in the locality.

Does the duration of illness before treatment affect the time taken to recover on treatment in severely depressed women?

This study examines the link between duration of depression before treatment is introduced and the duration of depressive illness after treatment in a population of 59 female psychiatric inpatients. Most women were suffering with severe depression and the majority had had previous depressive illnesses. Calculation of the rank order correlation coefficient demonstrated no significant correlation between the duration of depression before initiation of treatment and the duration after treatment was introduced. This finding is discussed in relation to other relevant studies.

Comparison of case fatality in south Asian and white patients after acute myocardial infarction: observational study

OBJECTIVE

To compare mortality in south Asian (Indian, Pakistani, and Bangladeshi) and white patients in the six months after hospital admission for acute myocardial infarction.

DESIGN

Observational study.

SETTING

District general hospital in east London.

PATIENTS

149 south Asian and 313 white patients aged < 65 years admitted to the coronary care unit with acute myocardial infarction from 1 December 1988 to 31 December 1992.

MAIN OUTCOME MEASURE

All cause mortality in the first six months after myocardial infarction.

RESULTS

The admission rate in the south Asians was estimated to be 2.04 times that in the white patients. Most aspects of treatment were similar in the two groups, except that a higher proportion of the south Asians received thrombolytic drugs (81.2% v 73.8%). After adjustment for age, sex, previous myocardial infarction, and treatment with thrombolysis or aspirin, or both, the south Asians had a poorer survival over the six months from myocardial infarction (hazard ratio 2.02 (95% confidence interval 1.14 to 3.56), P = 0.018), but a substantially higher proportion were diabetic (38% v 11%, P < 0.001), and additional adjustment for diabetes removed much of their excess risk (adjusted hazard ratio 1.26 (0.68 to 2.33), P = 0.47).

CONCLUSION

South Asian patients had a higher risk of admission with myocardial infarction and a higher risk of death over the ensuing six months than the white patients. The higher case fatality among the south Asians, largely attributable to diabetes, may contribute to the increased risk of death from coronary heart disease in south Asians living in Britain.