Louise Letley

Longitudinal study of infectious intestinal disease in the UK (IID2 study): incidence in the community and presenting to general practice

Objectives To estimate, overall and by organism, the incidence of infectious intestinal disease (IID) in the community, presenting to general practice (GP) and reported to national surveillance. Design Prospective, community cohort study and prospective study of GP presentation conducted between April 2008 and August 2009. Setting Eighty-eight GPs across the UK recruited from the Medical Research Council General Practice Research Framework and the Primary Care Research Networks. Participants 6836 participants registered with the 88 participating practices in the community study; 991 patients with UK-acquired IID presenting to one of 37 practices taking part in the GP presentation study. Main outcome measures IID rates in the community, presenting to GP and reported to national surveillance, overall and by organism; annual IID cases and GP consultations by organism. Results The overall rate of IID in the community was 274 cases per 1000 person-years (95% CI 254 to 296); the rate of GP consultations was 17.7 per 1000 person-years (95% CI 14.4 to 21.8). There were 147 community cases and 10 GP consultations for every case reported to national surveillance. Norovirus was the most common organism, with incidence rates of 47 community cases per 1000 person-years and 2.1 GP consultations per 1000 person-years. Campylobacter was the most common bacterial pathogen, with a rate of 9.3 cases per 1000 person-years in the community, and 1.3 GP consultations per 1000 person-years. We estimate that there are up to 17 million sporadic, community cases of IID and 1 million GP consultations annually in the UK. Of these, norovirus accounts for 3 million cases and 130 000 GP consultations, and Campylobacter is responsible for 500 000 cases and 80 000 GP consultations. Conclusions IID poses a substantial community and healthcare burden in the UK. Control efforts must focus particularly on reducing the burden due to Campylobacter and enteric viruses.

Effect of 2-y n−3 long-chain polyunsaturated fatty acid supplementation on cognitive function in older people: a randomized, double-blind, controlled trial

BACKGROUND Increased consumption of n-3 (omega-3) long-chain polyunsaturated fatty acids (LC PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may maintain cognitive function in later life. OBJECTIVE We tested the hypothesis that n-3 LC PUFA supplementation would benefit cognitive function in cognitively healthy older people. DESIGN At total of 867 cognitively healthy adults, aged 70-79 y, from 20 general practices in England and Wales were randomly assigned into a double-blind controlled trial of daily capsules providing 200 mg EPA plus 500 mg DHA or olive oil for 24 mo. Treatment-allocation codes were obtained from a central computerized randomization service. Trained research nurses administered a battery of cognitive tests, including the primary outcome, the California Verbal Learning Test (CVLT), at baseline and 24 mo. Intention-to-treat analysis of covariance, with adjustment for baseline cognitive scores, age, sex, and age at leaving full-time education, included 748 (86%) individuals who completed the study. RESULTS The mean age of participants was 75 y; 55% of the participants were men. Withdrawals and deaths were similar in active (n = 49 and n = 9, respectively) and placebo (n = 53 and n = 8, respectively) arms. Mean (+/-SD) serum EPA and DHA concentrations were significantly higher in the active arm than in the placebo arm at 24 mo (49.9 +/- 2.7 mg EPA/L in the active arm compared with 39.1 +/- 3.1 mg EPA/L in the placebo arm; 95.6 +/- 3.1 mg DHA/L in the active arm compared with 70.7 +/- 2.9 mg DHA/L in the placebo arm). There was no change in cognitive function scores over 24 mo, and intention-to-treat analysis showed no significant differences between trial arms at 24 mo in the CVLT or any secondary cognitive outcome. CONCLUSIONS Cognitive function did not decline in either study arm over 24 mo. The lack of decline in the control arm and the relatively short intervention period may have limited our ability to detect any potential beneficial effect of fish oil on cognitive function in this study. The Older People And n-3 Long-chain polyunsaturated fatty acids (OPAL) Study was registered at www.controlled-trials.com as ISRCTN 72331636.

Advice to use topical or oral ibuprofen for chronic knee pain in older people: randomised controlled trial and patient preference study

Objective To determine whether older patients with chronic knee pain should be advised to use topical or oral non-steroidal anti-inflammatory drugs (NSAIDs). Design Randomised controlled trial and patient preference study. Setting 26 general practices. Participants People aged ≥50 with knee pain: 282 in randomised trial and 303 in preference study. Interventions Advice to use topical or oral ibuprofen. Primary outcome measures WOMAC (Western Ontario and McMaster Universities) osteoarthritis index, major and minor adverse effects. Results Changes in global WOMAC scores at 12 months were equivalent. In the randomised trial the difference (topical minus oral) was two points (95% confidence interval −2 to 6); in the preference study, it was one point (−4 to 6). There were no differences in major adverse effects in the trial or study. The only significant differences in secondary outcomes were in the randomised trial. The oral group had more respiratory adverse effects (17% v 7%,95% confidence interval for difference −17% to −2%), the change in serum creatinine was 3.7 mmol/l less favourable (0.9 µmol/l to 6.5 µmol/l); and more participants changed treatments because of adverse effects (16% v 1%, −16% to −5%). In the topical group more participants had chronic pain grade III or IV at three months, and more participants changed treatment because of ineffectiveness. Conclusions Advice to use oral or topical preparations has an equivalent effect on knee pain over one year, and there are more minor side effects with oral NSAIDs. Topical NSAIDs may be a useful alternative to oral NSAIDs. Trial registration ISRCTN 79353052.

Topical intranasal corticosteroids in 4-11 year old children with persistent bilateral otitis media with effusion in primary care: double blind randomised placebo controlled trial

Objective To determine the clinical effectiveness of topical intranasal corticosteroids in children with bilateral otitis media with effusion. Design Double blind randomised placebo controlled trial. Setting 76 Medical Research Council General Practice Research Framework practices throughout the United Kingdom, between 2004 and 2007. Participants 217 children aged 4-11 years who had at least one practice recorded episode of otitis media or a related ear problem in the previous 12 months, and with bilateral otitis media with effusion confirmed by a research nurse using otoscopy plus micro-tympanometry (B/B or B/C2, modified Jerger types). Intervention Mometasone furoate 50 µg or placebo spray given once daily into each nostril for three months. Main outcome measures Proportions of children cured of bilateral otitis media with effusion assessed with tympanometry (C1 or A type) at one month (primary end point), three months, and nine months; adverse events; three month diary symptoms. Results 41% (39/96) of the topical steroid group and 45% (44/98) of the placebo group were cured in one or both ears at one month (difference favouring placebo 4.3% (95% confidence interval −9.3% to 18.1%). Poisson regression was done with adjustment for four pre-specified covariates (clinical severity, P=0.003; atopy, P=0.67; age, P=0.92; season, P=0.71). The adjusted relative risk at one month was 0.97 (95% confidence interval 0.74 to 1.26). At three months, 58% of the topical steroid group and 52% of the placebo group were cured (relative risk 1.23, 0.84 to 1.80). Diary symptoms did not differ between the two groups, and no significant harms were reported. Conclusions Topical steroids are unlikely to be an effective treatment for otitis media with effusion in general practice. High rates of natural resolution occurred by 1-3 months. Trial registration Current Controlled Trials ISRCTN38988331; National Research Register NO575123823; MREC 03/11/073.

Methods for determining disease burden and calibrating national surveillance data in the United Kingdom: the second study of infectious intestinal disease in the community (IID2 study)

BackgroundInfectious intestinal disease (IID), usually presenting as diarrhoea and vomiting, is frequently preventable. Though often mild and self-limiting, its commonness makes IID an important public health problem. In the mid 1990s around 1 in 5 people in England suffered from IID a year, costing around £0.75 billion. No routine information source describes the UKs current community burden of IID. We present here the methods for a study to determine rates and aetiology of IID in the community, presenting to primary care and recorded in national surveillance statistics. We will also outline methods to determine whether or not incidence has declined since the mid-1990s.Methods/designThe Second Study of Infectious Intestinal Disease in the Community (IID2 Study) comprises several separate but related studies. We use two methods to describe IID burden in the community - a retrospective telephone survey of self-reported illness and a prospective, all-age, population-based cohort study with weekly follow-up over a calendar year. Results from the two methods will be compared. To determine IID burden presenting to primary care we perform a prospective study of people presenting to their General Practitioner with symptoms of IID, in which we intervene in clinical and laboratory practice, and an audit of routine clinical and laboratory practice in primary care. We determine aetiology of IID using molecular methods for a wide range of gastrointestinal pathogens, in addition to conventional diagnostic microbiological techniques, and characterise isolates further through reference typing. Finally, we combine all our results to calibrate national surveillance data.DiscussionResearchers disagree about the best method(s) to ascertain disease burden. Our study will allow an evaluation of methods to determine the community burden of IID by comparing the different approaches to estimate IID incidence in its linked components.

A randomised controlled trial investigating the effect of n-3 long-chain polyunsaturated fatty acid supplementation on cognitive and retinal function in cognitively healthy older people: the Older People And n-3 Long-chain polyunsaturated fatty acids (OPAL) study protocol [ISRCTN72331636].

The number of individuals with age-related cognitive impairment is rising dramatically in the UK and globally. There is considerable interest in the general hypothesis that improving the diet of older people may slow the progression of cognitive decline. To date, there has been little attention given to the possible protective role of n-3 long-chain polyunsaturated fatty acids (n-3 LCPs) most commonly found in oily fish, in age-related loss of cognitive function. The main research hypothesis of this study is that an increased dietary intake of n-3 LCPs will have a positive effect on cognitive performance in older people in the UK.To test this hypothesis, a double-blind randomised placebo-controlled trial will be carried out among adults aged 70–79 years in which the intervention arm will receive daily capsules containing n-3 LCP (0.5 g/day docosahexaenoic acid and 0.2 g/day eicosapentaenoic acid) while the placebo arm will receive daily capsules containing olive oil. The main outcome variable assessed at 24 months will be cognitive performance and a second major outcome variable will be retinal function. Retinal function tests are included as the retina is a specifically differentiated neural tissue and therefore represents an accessible window into the functioning of the brain.The overall purpose of this public-health research is to help define a simple and effective dietary intervention aimed at maintaining cognitive and retinal function in later life. This will be the first trial of its kind aiming to slow the decline of cognitive and retinal function in older people by increasing daily dietary intake of n-3 LCPs. The link between cognitive ability, visual function and quality of life among older people suggests that this novel line of research may have considerable public health importance.

A double-blind randomised placebo-controlled trial of topical intranasal corticosteroids in 4- to 11-year-old children with persistent bilateral otitis media with effusion in primary care.

OBJECTIVES To determine the clinical effectiveness and cost-effectiveness of topical mometasone in children with bilateral otitis media with effusion (OME). DESIGN A double-blind randomised placebo-controlled trial with an intention to treat analysis; the 10.6% of patients lost to follow-up at 1 month were censored in the analysis. SETTING 76 Medical Research Council General Practice Research Framework practices throughout the UK between 2004 and 2007. PARTICIPANTS A sample of 217 children aged 4-11 years was selected from those presenting to their GP with one or more episodes of otitis media or ear-related problems in the previous 12 months whom the research nurse confirmed had bilateral glue ear using microtympanometry (B B or B C2 types using a modified Jerger classification) at randomisation. INTERVENTIONS Mometasone 50 micrograms in each nostril or placebo spray once daily for 3 months. MAIN OUTCOME MEASURES The primary outcome was the proportions of children cleared of OME assessed by tympanometry at 1 month. Secondary outcomes included clearance at 3 months and 9 months; adverse events; OM8-30 scores (a functional health status responsive disease-specific measure); hearing loss; days with otalgia; cost-effectiveness; and health utilities. RESULTS Of the topical steroid group, 40.6% (39/96) demonstrated tympanometric clearance (C1 or A type) in one or both ears at 1 month, compared with 44.9% (44/98) of the placebo group. The absolute risk reduction at 1 month was -4.3% (95% CI -18.05% to 9.26%); the odds ratio (OR) was 0.84 (95% CI 0.48 to 1.48). Four covariates were pre-specified for inclusion in logistic regression analysis: age as a continuous variable (p = 0.94), season (p = 0.70), atopy (p = 0.61) and clinical severity (p = 0.006). The adjusted OR (AOR) at 1 month for the main outcome was 0.93 (95% CI 0.50 to 1.75). Secondary analysis at 3 months showed 58.1% of the steroid group had resolved and 52.3% of the placebo group, AOR 1.45 (95% CI 0.74 to 2.84). At 9 months 55.6% of the treated group remained clear in at least one ear and 65.3% of the placebo group, AOR 0.82 (95% CI 0.39 to 1.75). Adverse events (although relatively minor) occurred in 7-22% of children and included nasal stinging, epistaxis, dry throat and cough. The OM8-30 scores (p = 0.55) reported hearing difficulty (p = 0.08), and days with otalgia (p = 0.46) were not significantly different between groups at 3 months. The economic evaluation found the active treatment arm to be dominated by placebo, accruing slightly (but not significantly) higher costs and fewer quality-adjusted life-years (QALYs), with a 24.2% probability that topical steroids are a cost-effective use of NHS resources at a ceiling ratio of 20,000 pounds per QALY gained. CONCLUSIONS Use of topical intranasal corticosteroids is very unlikely to be a clinically effective treatment for OME (glue ear) in the primary care setting. TRIAL REGISTRATION Current Controlled Trials ISRCTN38988331.

Effects of vitamin B-12 supplementation on neurologic and cognitive function in older people: a randomized controlled trial

Background: Moderate vitamin B-12 deficiency is relatively common in older people. However, there is little robust evidence on the effect of vitamin B-12 supplementation on neurologic and cognitive outcomes in later life. Objective: We investigated whether vitamin B-12 supplementation benefits neurologic and cognitive function in moderately vitamin B-12–deficient older people. Design: We conducted a double-blind, randomized, placebo-controlled trial in 7 general practices in South East England, United Kingdom. Study participants were aged ≥75 y and had moderate vitamin B-12 deficiency (serum vitamin B-12 concentrations: 107–210 pmol/L) in the absence of anemia and received 1 mg crystalline vitamin B-12 or a matching placebo as a daily oral tablet for 12 mo. Peripheral motor and sensory nerve conduction, central motor conduction, a clinical neurologic examination, and cognitive function were assessed before and after treatment. Results: A total of 201 participants were enrolled in the trial, and 191 subjects provided outcome data. Compared with baseline, allocation to vitamin B-12 was associated with a 177% increase in serum concentration of vitamin B-12 (641 compared with 231 pmol/L), a 331% increase in serum holotranscobalamin (240 compared with 56 pmol/L), and 17% lower serum homocysteine (14.2 compared with 17.1 μmol/L). In intention-to-treat analysis of covariance models, with adjustment for baseline neurologic function, there was no evidence of an effect of supplementation on the primary outcome of the posterior tibial compound muscle action potential amplitude at 12 mo (mean difference: −0.2 mV; 95% CI: –0.8, 0.3 mV). There was also no evidence of an effect on any secondary peripheral nerve or central motor function outcome, or on cognitive function or clinical examination. Conclusion: Results of the trial do not support the hypothesis that the correction of moderate vitamin B-12 deficiency, in the absence of anemia and of neurologic and cognitive signs or symptoms, has beneficial effects on neurologic or cognitive function in later life. This trial was registered at www.isrctn.com as ISRCTN54195799.

A randomised controlled trial investigating the effect of vitamin B12 supplementation on neurological function in healthy older people: the Older People and Enhanced Neurological function (OPEN) study protocol [ISRCTN54195799]

BackgroundVitamin B12 deficiency is common in older people and the prevalence increases with age. Vitamin B12 deficiency may present as macrocytic anaemia, subacute combined degeneration of the spinal cord, or as neuropathy, but is often asymptomatic in older people. The diagnosis and indications for treatment are clear for individuals with low plasma levels of vitamin B12 in the setting of megaloblastic anaemia and neuropathy, but the relevance of treatment of vitamin B12 deficiency in the absence of such clinical signs is uncertain.MethodsThe aim of the present study is to assess whether dietary supplementation with crystalline vitamin B12 will improve electrophysiological indices of neurological function in older people who have biochemical evidence of vitamin B12 insufficiency in the absence of anaemia. To test this hypothesis we designed a randomized double-blind placebo-controlled trial involving 200 older people aged 75 years or greater who were randomly allocated to receive either a daily oral tablet containing 1 mg vitamin B12 or a matching placebo tablet. The primary outcome assessed at 12 months is change in electrophysiological indices of peripheral and central neurosensory responses required for mobility and sensory function. We here report the detailed study protocol.ConclusionsIn view of the high prevalence of vitamin B12 deficiency in later life, the present trial could have considerable significance for public health.

Cumulative flying time and risk of venous thromboembolism

The risk of venous thromboembolism (VTE) associated with cumulative flying time remains uncertain. In a case–control study in general practices throughout the UK, participants comprised 550 VTE cases identified from practice records and 1971 age‐ and gender‐matched controls. Participants returned identical questionnaires asking for information including air travel details. Compared to not flying, cumulative flying time >12 h within the previous 4 weeks was associated with a threefold increase in the risk of VTE [odds ratio (OR) 2·75, 95% confidence interval (CI), 1·44–5·28]. Those who had flown >4 h in a single leg in the previous 4 weeks had twice the risk of VTE (OR 2·20, 95% CI, 1·29–3·73). These risks were no longer evident by 12 weeks and were similar to those of day‐case or minor surgery (OR 5·35, 95% CI, 2·15–13·33). Equivalent risks for moderate and high‐risk surgery were over 30‐fold (OR 36·57, 95% CI, 13·05–102·52) and 140‐fold (OR 141·71, 95% CI, 19·38–1036·01) respectively. The temporary nature of the association of cumulative and long‐haul air travel with VTE suggests a causal relationship. The risks of VTE in those with a higher baseline risk due to surgery, previous VTE or obesity are further increased by air travel.