COVID-19 in non-hospitalised adults caused by either SARS-CoV-2 sub-variants Omicron BA.1, BA.2, BA.4/5 or Delta associates with similar illness duration, symptom severity and viral kinetics, irrespective of vaccination history

BACKGROUND

SARS-CoV-2 variant Omicron rapidly evolved over 2022, causing three waves of infection due to sub-variants BA.1, BA.2 and BA.4/5. We sought to characterise symptoms and viral loads over the course of COVID-19 infection with these sub-variants in otherwise-healthy, vaccinated, non-hospitalised adults, and compared data to infections with the preceding Delta variant of concern (VOC).

METHODS

In a prospective, observational cohort study, healthy vaccinated UK adults who reported a positive polymerase chain reaction (PCR) or lateral flow test, self-swabbed on alternate weekdays until day 10. We compared participant-reported symptoms and viral load trajectories between infections caused by VOCs Delta and Omicron (sub-variants BA.1, BA.2 or BA.4/5), and tested for relationships between vaccine dose, symptoms and PCR cycle threshold (Ct) as a proxy for viral load using Chi-squared (χ2) and Wilcoxon tests.

RESULTS

563 infection episodes were reported among 491 participants. Across infection episodes, there was little variation in symptom burden (4 [IQR 3-5] symptoms) and duration (8 [IQR 6-11] days). Whilst symptom profiles differed among infections caused by Delta compared to Omicron sub-variants, symptom profiles were similar between Omicron sub-variants. Anosmia was reported more frequently in Delta infections after 2 doses compared with Omicron sub-variant infections after 3 doses, for example: 42% (25/60) of participants with Delta infection compared to 9% (6/67) with Omicron BA.4/5 (χ2 P < 0.001; OR 7.3 [95% CI 2.7-19.4]). Fever was less common with Delta (20/60 participants; 33%) than Omicron BA.4/5 (39/67; 58%; χ2 P = 0.008; OR 0.4 [CI 0.2-0.7]). Amongst infections with an Omicron sub-variants, symptoms of coryza, fatigue, cough and myalgia predominated. Viral load trajectories and peaks did not differ between Delta, and Omicron, irrespective of symptom severity (including asymptomatic participants), VOC or vaccination status. PCR Ct values were negatively associated with time since vaccination in participants infected with BA.1 (β = -0.05 (CI -0.10-0.01); P = 0.031); however, this trend was not observed in BA.2 or BA.4/5 infections.

CONCLUSION

Our study emphasises both the changing symptom profile of COVID-19 infections in the Omicron era, and ongoing transmission risk of Omicron sub-variants in vaccinated adults.

TRIAL REGISTRATION

NCT04750356.

Combined analyses of within-host SARS-CoV-2 viral kinetics and information on past exposures to the virus in a human cohort identifies intrinsic differences of Omicron and Delta variants

The emergence of successive Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) during 2020 to 2022, each exhibiting increased epidemic growth relative to earlier circulating variants, has created a need to understand the drivers of such growth. However, both pathogen biology and changing host characteristics-such as varying levels of immunity-can combine to influence replication and transmission of SARS-CoV-2 within and between hosts. Disentangling the role of variant and host in individual-level viral shedding of VOCs is essential to inform Coronavirus Disease 2019 (COVID-19) planning and response and interpret past epidemic trends. Using data from a prospective observational cohort study of healthy adult volunteers undergoing weekly occupational health PCR screening, we developed a Bayesian hierarchical model to reconstruct individual-level viral kinetics and estimate how different factors shaped viral dynamics, measured by PCR cycle threshold (Ct) values over time. Jointly accounting for both interindividual variation in Ct values and complex host characteristics-such as vaccination status, exposure history, and age-we found that age and number of prior exposures had a strong influence on peak viral replication. Older individuals and those who had at least 5 prior antigen exposures to vaccination and/or infection typically had much lower levels of shedding. Moreover, we found evidence of a correlation between the speed of early shedding and duration of incubation period when comparing different VOCs and age groups. Our findings illustrate the value of linking information on participant characteristics, symptom profile and infecting variant with prospective PCR sampling, and the importance of accounting for increasingly complex population exposure landscapes when analysing the viral kinetics of VOCs. Trial Registration: The Legacy study is a prospective observational cohort study of healthy adult volunteers undergoing weekly occupational health PCR screening for SARS-CoV-2 at University College London Hospitals or at the Francis Crick Institute (NCT04750356) (22,23). The Legacy study was approved by London Camden and Kings Cross Health Research Authority Research and Ethics committee (IRAS number 286469). The Legacy study was approved by London Camden and Kings Cross Health Research Authority Research and Ethics committee (IRAS number 286469) and is sponsored by University College London Hospitals. Written consent was given by all participants.

Within-host SARS-CoV-2 viral kinetics informed by complex life course exposures reveals different intrinsic properties of Omicron and Delta variants

The emergence of successive SARS-CoV-2 variants of concern (VOC) during 2020-22, each exhibiting increased epidemic growth relative to earlier circulating variants, has created a need to understand the drivers of such growth. However, both pathogen biology and changing host characteristics - such as varying levels of immunity - can combine to influence replication and transmission of SARS-CoV-2 within and between hosts. Disentangling the role of variant and host in individual-level viral shedding of VOCs is essential to inform COVID-19 planning and response, and interpret past epidemic trends. Using data from a prospective observational cohort study of healthy adult volunteers undergoing weekly occupational health PCR screening, we developed a Bayesian hierarchical model to reconstruct individual-level viral kinetics and estimate how different factors shaped viral dynamics, measured by PCR cycle threshold (Ct) values over time. Jointly accounting for both inter-individual variation in Ct values and complex host characteristics - such as vaccination status, exposure history and age - we found that age and number of prior exposures had a strong influence on peak viral replication. Older individuals and those who had at least five prior antigen exposures to vaccination and/or infection typically had much lower levels of shedding. Moreover, we found evidence of a correlation between the speed of early shedding and duration of incubation period when comparing different VOCs and age groups. Our findings illustrate the value of linking information on participant characteristics, symptom profile and infecting variant with prospective PCR sampling, and the importance of accounting for increasingly complex population exposure landscapes when analysing the viral kinetics of VOCs.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

758 Online Surgical Journal Clubs: Are They Effective?

Aim

Much of medical education has been abruptly forced online during the COVID-19 pandemic. Traditional journal clubs thrive on group interaction and debate. The aim of this project is to assess whether an online surgical journal club could replicate this experience and learning.

Method

A fortnightly, chat-based online surgical journal club with national reach was re-launched under SCALPEL (Manchester Medical School’s surgical society) with defined learning objectives, inclusion of studies from different surgical sub-specialities and a proforma to aid critical appraisal. Anonymous feedback forms were sent to participants to assess confidence in critically appraising the literature before and after attendance, and differences in means were analysed using paired t-test.

Results

32 feedback forms from participants, the majority of whom were final year medical students (34.4%) were analysed. 28.1% had previously attended a journal club. 65.6% of attendees had prior involvement in a research project which led to a publication for 18.8%, while 59.4% were interested in applying for the Academic Foundation Programme (AFP). The self-reported confidence of participants to identify the study design, interpret the results and statistical analyses; and scrutinise the strengths and weaknesses of a study increased by 12.2%, 14.7% and 15.9% respectively (p = &lt;0.001). Furthermore, 96.9% of attendees stated they would attend another online journal club in the future, with 59.4% favouring an online format.

Conclusions

Online surgical journal clubs are effective and are here to stay following the conclusion of social distancing. They have the advantage of further outreach and may encourage greater participation than traditional journal clubs.

Cost-effectiveness of imaging strategies to diagnose and select patients with non-obstructive coronary artery disease for statin treatment in the United Kingdom

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): The project leading to this publication has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 668142.

Background

Patients with non-obstructive coronary artery disease (NOCAD) are at a higher risk of cardiovascular events compared to those with normal arteries. Plaque rupture is associated with increased adverse events and statin therapy seems to be beneficial for plaque stabilisation. Coronary Computed Tomography Angiography (CCTA) is currently the non-invasive imaging modality of choice for the morphological evaluation of NOCAD in the United Kingdom (UK). However, CCTA provides limited information regarding the vulnerability of plaques to rupture and the selection of patients for preventive statin treatment. Currently being tested on patients, Spectral Photon-Counting CT (SPCCT) may provide increased accuracy for vulnerable plaque detection and, in turn, improved selection of patients for statin treatment.

Purpose

We investigated the potential cost-effectiveness of SPCCT (compared to a set of CCTA-based strategies) in identifying NOCAD patients with rupture-prone plaques for preventive statin treatment.

Methods

A decision tree and a Markov trace were developed to model the expected outcomes (costs and quality-adjusted life-years (QALYs)) for a hypothetical UK cohort of 50-year-old male patients with stable chest pain and no history of CAD. Input data were obtained from the literature. Deterministic and probabilistic sensitivity analyses were performed. The impact of a pairwise variation of SPCCT sensitivity and specificity was analysed. Furthermore, five competing imaging strategies were compared in terms of their lifetime costs and effects: 1) CCTA and treat NOCAD based on imaging results, 2) CCTA and treat all NOCAD, 3) CCTA and do not treat NOCAD, 4) SPCCT with high specificity and treat NOCAD based on imaging results, and 5) SPCCT with high sensitivity and treat NOCAD based on imaging results.

Results

Our deterministic and probabilistic results showed that an improved imaging test would add value compared to CCTA. While increased specificity (to 95%) is favorable at a lower willingness to pay (WTP) (up to ∼£9,000 per QALY), increased sensitivity (to 95%) is more likely to be favorable at a higher WTP (∼£9,000 to £120,000 per QALY). The role of a CCTA-treat-none strategy and a CCTA-treat-all strategy is minimal and potential only at really low (&lt;£2,000 per QALY) and high (&gt;£120,000 per QALY) WTP, respectively. The uncertainty around these results is highly correlated to the uncertainty around the long-term risk for NOCAD patients to experience myocardial infarction or stroke.

Conclusion

An improved imaging test based on higher sensitivity in identifying rupture-prone coronary plaques in NOCAD patients seems to have value in guiding the decision of preventive statin treatment in the UK. However, additional data regarding the efficacy of statins and of combined treatments for NOCAD patients are needed before the cost-effectiveness of SPCCT can be precisely estimated in this population.

Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients

AIM

To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD).

MATERIALS AND METHODS

Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥ 50%) stenosis and secondarily as the presence of severe (≥ 70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard.

RESULTS

No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis.

CONCLUSION

The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role.

Transcatheter aortic valve insertion (TAVI): a review

The introduction of transcatheter aortic valve insertion (TAVI) has transformed the care provided for patients with severe aortic stenosis. The uptake of this procedure is increasing rapidly, and clinicians from all disciplines are likely to increasingly encounter patients being assessed for or having undergone this intervention. Successful TAVI heavily relies on careful and comprehensive imaging assessment, before, during and after the procedure, using a range of modalities. This review outlines the background and development of TAVI, describes the nature of the procedure and considers the contribution of imaging techniques, both to successful intervention and to potential complications.

The risk to the United Kingdom population of zinc cadmium sulfide dispersion by the Ministry of Defence during the "cold war"

OBJECTIVES

To estimate exposures to cadmium (Cd) received by the United Kingdom population as a result of the dispersion of zinc Cd sulfide (ZnCdS) by the Ministry of Defence between 1953 and 1964, as a simulator of biological warfare agents.

METHODS

A retrospective risk assessment study was carried out on the United Kingdom population during the period 1953-64. This determined land and air dispersion of ZnCdS over most of the United Kingdom, inhalation exposure of the United Kingdom population, soil contamination, and risks to personnel operating equipment that dispersed ZnCdS.

RESULTS

About 4600 kg ZnCdS were dispersed from aircraft and ships, at times when the prevailing winds would allow large areas of the country to be covered. Cadmium released from 44 long range trials for which data are available, and extrapolated to a total of 76 trials to allow for trials with incomplete information, is about 1.2% of the estimated total release of Cd into the atmosphere over the same period. "Worst case" estimates are 10 microg Cd inhaled over 8 years, equivalent to Cd inhaled in an urban environment in 12100 days, or from smoking 100 cigarettes. A further 250 kg ZnCdS was dispersed from the land based sites, but significant soil contamination occurred only in limited areas, which were and have remained uninhabited. Of the four personnel involved in the dispersion procedures (who were probably exposed to much higher concentrations of Cd than people on the ground), none are suspected of having related illnesses.

CONCLUSION

Exposure to Cd from dissemination of ZnCdS during the "cold war" should not have resulted in adverse health effects in the United Kingdom population.

Impairment of osmotically stimulated AVP release in patients with primary polydipsia

The secretion of arginine vasopressin (AVP) from the posterior pituitary is primarily and finely regulated by the osmolality of plasma. Even though a number of factors alter osmolality-induced release of AVP, there are no published data in humans that have addressed the role of chronic overhydration on this phenomenon. To address this problem we have identified eight patients with primary polydipsia using criteria not involving measurement of AVP, and have subjected them to standardized infusions of hypertonic saline. These patients had less AVP in both plasma and urine in relation to plasma osmolality than was found in normal subjects. In addition, their rate of rise of plasma and urine AVP was less than in normal subjects. Their osmotic threshold for AVP release may have been higher than normal. These data demonstrate that chronic overhydration in humans downregulates the release of AVP in response to hypertonicity. This phenomenon may explain the impairment of urine concentration in patients with primary polydipsia and emphasizes the basis of the difficulty that may occur clinically in differentiating between patients with primary polydipsia and partial central diabetes insipidus.

Gallbladder function in acromegalic patients taking long-term octreotide: evidence of rebound hypermotility on cessation of treatment

Octreotide is increasingly being used in the treatment of acromegaly. It effectively suppresses growth hormone secretion but also has inhibitory effects on gastrointestinal regulatory peptides and induces gallbladder paresis, which may predispose to gallstone formation. In nine acromegalic patients receiving long-term octreotide treatment gallbladder emptying, assessed by 99Tc-EHIDA scintigraphy after a standard fatty meal, was significantly impaired (p less than 0.005) when compared with normal healthy control subjects. Asymptomatic gallstone formation occurred in one patient who had the most severely impaired gallbladder emptying. Between 24 and 96 h after cessation of octreotide, in six of seven patients studied, gallbladder emptying had not only recovered but demonstrated significant rebound hypermotility (p less than 0.005). This finding has important implications for the administration of long-term octreotide therapy and suggests that a drug-free period each week may enable evacuation of gallbladder contents and reduce the risk of gallstone formation.

Use of T1-weighted MR imaging to differentiate between primary polydipsia and central diabetes insipidus

PURPOSE

To investigate the value of MR in differentiating patients with primary polydipsia, who have an intact neurohypophyseal system, from those with central diabetes insipidus, who have impaired synthesis and/or release of vasopressin.

METHODS

Eighteen patients with clinically significant hypotonic polyuria were diagnosed endocrinologically as having primary polydipsia or diabetes insipidus (central or nephrogenic). These patients, and 92 patients without sellar disease, were then imaged with 1.5-T, T1-weighted, thin sagittal sections without gadolinium contrast.

RESULTS

Normal hyperintense signal of the neurohypophysis was present in 90 of 92 patients without sellar disease. The signal was also present in all six patients with primary polydipsia. In contrast, the hyperintense signal was absent in all eight patients with central diabetes insipidus. Three of the four patients with nephrogenic diabetes insipidus also had an absent hyperintense signal.

CONCLUSION

T1-weighted MR may prove important in differentiating patients with central diabetes insipidus from those with primary polydipsia.

A comparison of measurements of lean body mass derived by bioelectrical impedance, skinfold thickness and total body potassium. A study in obese and non-obese normal subjects

The measurement of body composition is an important part of metabolic and epidemiological research, but most currently available methods are complex and expensive. We have, therefore, compared measurements of fat mass (FM) and lean body mass (LBM), obtained using a commercially available bioelectrical impedance monitor (The Holtain Body Composition Monitor) (IMP), and by measuring skinfold thickness (SFT), with values obtained by measuring total body potassium (TBK). Twenty subjects, 10 with a body mass index (BMI) less than 30 (kg m-2), (non-obese) and 10 with BMI greater than or equal to 30 (obese) took part in the study. There was a strongly significant linear relationship between LBM calculated from TBK and that calculated from impedance (IMP), in both non-obese and obese groups analysed separately (non-obese: r = 0.92; p less than 0.001 and obese: r = 0.92; p less than 0.001) and together (all: r = 0.89; p less than 0.001). LBM calculated from TBK was strongly linearly correlated with values derived from SFT for non-obese (r = 0.91; p less than 0.001) but not for obese subjects. Mean values of LBM of non-obese subjects derived by each method were not significantly different (TBK: 51.3 +/- 10.40 kg; IMP: 53.18 +/- 10.37 kg; SFT: 48.87 +/- 9.48 kg), but significant differences existed when the subjects were obese (TBK: 51.86 +/- 9.65 kg; IMP: 58.69 +/- 8.55 kg; SFT: 67.61 +/- 8.14 kg; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Total-body potassium in insulin-dependent diabetes mellitus

1. Total-body potassium and fat-free mass have been measured in 31 insulin-dependent diabetic patients and 31 age- and sex-matched normal volunteers. 2. Body mass index was significantly higher in the insulin-dependent diabetic patients (24.7 +/- 0.5 vs 23.3 +/- 0.4 kg/m2; P = 0.05). 3. Total-body potassium, uncorrected and corrected for weight and for fat-free mass, was not significantly different in the two groups (3281 +/- 141 mmol, 47.3 +/- 1.3 mmol/kg body weight, 60.9 +/- 1.0 mmol/kg fat-free mass, and 3315 +/- 143 mmol, 48.6 +/- 1.0 mmol/kg body weight, 60.4 +/- 0.8 mmol/kg fat-free mass, respectively, in diabetic patients and non-diabetic subjects). There was no relationship between blood glucose control, as assessed by glycated haemoglobin concentrations, and total-body potassium. 4. These results suggest, by contrast with previous reports, that in insulin-dependent diabetic patients, showing varying degrees of glycaemic control (glycated haemoglobin range 6.1-15.3%, mean 9.0%) that: (a) there is no significant abnormality of body potassium homoeostasis, and (b) there is no relation between total-body potassium and glycaemic control.

Thallium isotope scintigraphy and ultrasonography: comparative studies of localization techniques in primary hyperparathyroidism

Controversy exists about whether preoperative localization procedures are indicated in patients with primary hyperparathyroidism before first neck exploration. Currently, thallium subtraction scintigraphy and ultrasonography are the techniques used most frequently. This paper examines prospectively the accuracy and value of these techniques in a group of 71 patients with primary hyperparathyroidism. When considering all glands, thallium scanning produced a sensitivity of 46.6 per cent with a specificity of 91.5 per cent, compared with a sensitivity of only 21.4 per cent and specificity of 94.5 per cent for ultrasonography. Accuracy rates, for all glands, were 80 per cent and 75.7 per cent respectively. Both localization procedures were consistently ineffective in localizing adenomas weighing less than 500 mg, over 80 per cent of which went undetected by both scanning modalities. While both scans produced satisfactory results in localizing adenomas weighing more than 1 g, these adenomas should not represent a challenge to an experienced endocrine surgeon and, therefore, neither localization is recommended before first neck exploration.

The effect of pH adjustment of 0.5% bupivacaine on the latency of epidural anesthesia

pH adjustment of lidocaine and 2-chloroprocaine has been reported to decrease the latency of epidural anesthesia (EA). The effect of alkalinization of bupivacaine on onset of surgical anesthesia has not been adequately studied to date. To determine what effect raising the pH of 0.5% bupivacaine has on the latency of EA in patients undergoing lower extremity surgery, we performed a randomized, double-blind study. Forty patients were randomly divided into two groups. Group I patients received 15 ml of a local anesthetic (LA) solution containing 0.5% bupivacaine and 0.15 mEq of NaHCO3. Group II patients received 15 ml of a standard solution of 0.5% bupivacaine. Both solutions contained freshly added epinephrine (1:200,000). After injection of LA via Tuohy needle, sensory testing was conducted using a safety pin. The pH of the LA used for Group I was 6.96 +/- 0.01 and for Group II was 5.33 +/- 0.11. No statistically significant difference was found between the anesthetic parameters tested in each group. On this basis, we find no advantage of pH adjustment of 0.5% bupivacaine for EA.

Reduced concentrations of selenium in mild Crohn's disease

The concentrations of selenium, zinc, and copper were determined in whole blood, plasma, and leucocytes in 20 patients with relatively mild Crohn's disease, nine of whom were being treated with steroids, and compared with those of a control group. There was a significant decrease in the concentration of selenium in the leucocytes as well as in whole blood and plasma in the patients. Steroids seemed to affect only the concentrations of zinc and copper in plasma. The concentrations of copper and zinc in whole blood, plasma, and leucocytes in patients not taking steroids were not significantly different from those of the control group. The observations suggest that those patients with an apparently satisfactory whole body concentration of copper and zinc may still be at risk of a decrease in the body content of selenium.

Effects of tap water lead, water hardness, alcohol, and cigarettes on blood lead concentrations

A survey of middle-aged men in 24 British towns has found pronounced geographical variation in blood lead concentrations. Towns with the highest mean blood lead concentrations have soft water supplies and have the highest water lead concentrations. Individual blood lead can be considerably increased by raised household tap water lead concentrations. Mean blood lead is estimated to be 43% higher for men when the concentration of lead in first-draw domestic tap water is 100 micrograms/l compared with a zero concentration. Individual blood lead is also affected by alcohol consumption and cigarette smoking, such that on average these two life-style habits together contribute an estimated 17% to the blood concentration of lead in middle-aged men. Lead in water should be given greater priority in any national campaign to reduce lead exposure.

Effects of alcohol and smoking on blood lead in middle-aged British men

A survey of middle-aged men in 24 British towns showed a strong association between blood lead concentrations, alcohol consumption, and cigarette smoking. The association with alcohol persisted after age, social class, body mass index, cigarette smoking, water lead concentrations, and the town of residence had been taken into account. There was an independent but less pronounced association between cigarette smoking and blood lead concentrations after adjustment for the other factors. The possible mechanisms include a decreased excretion of lead due to alcohol-induced hepatic dysfunction and an increased lead intake from cigarette smoking. These findings have implications for widespread measurement of blood lead concentrations in adults in the community and for all studies attempting to relate blood lead concentrations to environmental exposure.

Inherited disorders of 3-methylcrotonyl CoA carboxylation

The clinical course of 4 patients who had reduced activities of 3-methylcrotonyl CoA carboxylase (also called 3-methylcrotonylglycinuria) is described. Two children presented with a metabolic acidosis, one in the neonatal period and the other with episodes of acidosis that started in the second year of life. In the other 2 children neurological symptoms were prominent, one having infantile spasms and the other developmental regression with a skin rash and alopecia. Three of the children responded well to oral biotin and dietary protein restriction but the fourth, despite a biochemical response to biotin, has a severe neurological handicap. The clinical presentation of inborn errors of 3-methylcrotonyl CoA carboxylase is variable. Metabolic acidosis may not be conspicuous and instead neurological features may predominate.

Thyroid-stimulating immunoglobulins in ophthalmic Graves' disease

Thyroid-stimulating immunoglobulins (TSI) have been detected by receptor assay in the sera of 43% of patients with ophthalmic Graves' disease. Comparison of the receptor assay studies with thyroid function tests indicated that in several patients the antibodies detected by receptor assay were biologically inactive. In other patients, thyroid function appeared to be under TSI control with hyperthyroidism prevented by autoimmune destruction of the thyroid.

Use of creatine kinase for detecting severe X-linked muscular dystrophy carriers

Women thought to be at risk of being carriers of Duchenne muscular dystrophy were given "odds" against their having an affected child. These were calcuated from a combination of the genetic risk from the family history and an estimation of the biochemical risk from measuring the serum creatine kinase concentration. The women were told the actual risk estimate and it was put into perspective for them as a high, medium, or low risk. Of 25 women at high risk six have had children, all girls; the two in the medium-risk group have had no children; and the 46 women at low risk have had 19 boys and 25 girls. None of the boys has the disease. With detailed counselling most potential carriers of this disease reach decisions in child bearing that are in line with their degree of risk.