Participation, retention and uptake in a multicentre pre-exposure prophylaxis cohort using online, smartphone-compatible data collection.

OBJECTIVES: The aim of the study was to assess the feasibility of a national pre-exposure prophylaxis (PrEP) programme using smartphone-compatible data collection. METHODS: This was a multicentre cohort study (NCT03893188) enrolling individuals interested in PrEP in Switzerland. All centres participate in the SwissPrEPared programme, which uses smartphone-compatible data collection. Feasibility was assessed after centres had enrolled at least one participant. Participants were HIV-negative individuals presenting for PrEP counselling. Outcomes were participation (number enrolled/number eligible), enrolment rates (number enrolled per month), retention at first follow-up (number with first follow-up/number enrolled), and uptake (proportion attending first visit as scheduled). Participant characteristics were compared between those retained after baseline assessment and those who dropped out. RESULTS: Between April 2019 and January 2020, 987 individuals were assessed for eligibility, of whom 969 were enrolled (participation: 98.2%). The median enrolment rate was 86 per month [interquartile range (IQR) 52-137]. Retention at first follow-up and uptake were both 80.7% (782/969 and 532/659, respectively). At enrolment, the median age was 40 (IQR 33-47) years, 95% were men who have sex with men, 47% had a university degree, and 75.5% were already taking PrEP. Most reported multiple casual partners (89.2%), previous sexually transmitted infections (74%) and sexualized drug use (73.1%). At baseline, 25.5% tested positive for either syphilis, gonorrhoea or chlamydia. Participants who dropped out were at lower risk of HIV infection than those retained after baseline assessment. CONCLUSIONS: In a national PrEP programme using smartphone-compatible data collection, participation, retention and uptake were high. Participants retained after baseline assessment were at considerable risk of HIV infection. Younger, less educated individuals were underrepresented in the SwissPrEPared cohort.

Practicality and Reliability of Self Vs Administered Rapid Geriatric Assessment Mobile App.

OBJECTIVES: To develop and cross-validate self-administered Rapid Geriatric Assessment (SA-RGA) app against administered Rapid Geriatric Assessment (A-RGA) to identify seniors with geriatric syndromes such as frailty, sarcopenia, and anorexia of ageing who may benefit from targeted intervention. DESIGN: Prospective observational study. SETTING: Primary Care and Community. PARTICIPANTS: A-RGA and SA-RGA app were administered to older adults ≥ 60 years old from December 2020 to April 2021. MEASUREMENTS: The RGA app screens for frailty (FRAIL), sarcopenia (SARC-F), anorexia of aging (SNAQ) and cognition (Rapid Cognitive Screen) with assisted management pathway. Patient Health Questionnaire 9 is administered for those who score positive for fatigue. The diagnostic performance of SA-RGA was compared against A-RGA as a reference by calculating the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and positive likelihood ratio (+LR). RESULTS: 123 participants with a mean age of 71 ± 5.9 years completed both the SA-RGA and A-RGA. Questions on fatigue, 5 or more illnesses, loss of weight and falls in the past year performed better with high sensitivity, specificity, NPV and +LR than self-functional assessment where SA-RGA participants reported lower prevalence on the FRAIL scale aerobic and resistance components, and higher prevalence on the SARC-F strength and rising from a chair components. CONCLUSION: The SA-RGA app performed well in certain domains such as assessment for weight loss, falls, number of chronic illness and fatigue. Self-functional assessment can be improved further by removing ambiguity in wordings such as "some" or "a lot" and replacing it with functional difficulty scale. SA-RGA has the potential to be incorporated in the eHEALTH platforms worldwide for early identifications of older adults at risk and to reduce health inequalities, at the same time building community resilience in the era of Covid-19 pandemic.

Prenatal Substance Use Disorders and Dental Caries in Children.

Substance use is common in women of reproductive age, but limited data exist on the dental health of their children, including risk of caries. We conducted a longitudinal cohort study of 790,758 infants born between 2006 and 2016 in Quebec, Canada. We identified women with substance use disorders before or during pregnancy. The main outcome measure was hospitalization for dental caries in offspring up to 12 y after birth. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for the association of maternal substance use with pediatric dental caries, adjusted for potential confounders. Children exposed to maternal substance use had a higher incidence of hospitalization for dental caries than unexposed children (105.2 vs. 27.0 per 10,000 person-years). Maternal substance use was associated with 1.96 times the risk of childhood dental caries (95% CI, 1.80-2.14), including a greater risk of caries of enamel, dentin, or cementum (HR, 2.00; 95% CI, 1.82-2.19) and dental pulp (HR, 2.36; 95% CI, 2.07-2.70), relative to no substance use. Associations were elevated for alcohol (HR, 2.31; 95% CI, 2.03-2.64) but were also present for cocaine, cannabis, opioids, and other substances. Substance use during pregnancy was more strongly associated with dental caries hospitalization than prepregnancy substance use. Associations were stronger in early childhood. Maternal substance use is associated with the future risk of dental caries hospitalization in children. Targeting substance use early in the lives of women may contribute to dental caries prevention in offspring.

Ebola virus disease outbreak in Nigeria: Transmission dynamics and rapid control.

International air travel has already spread Ebola virus disease (EVD) to major cities as part of the unprecedented epidemic that started in Guinea in December 2013. An infected airline passenger arrived in Nigeria on July 20, 2014 and caused an outbreak in Lagos and then Port Harcourt. After a total of 20 reported cases, including 8 deaths, Nigeria was declared EVD free on October 20, 2014. We quantified the impact of early control measures in preventing further spread of EVD in Nigeria and calculated the risk that a single undetected case will cause a new outbreak. We fitted an EVD transmission model to data from the outbreak in Nigeria and estimated the reproduction number of the index case at 9.0 (95% confidence interval [CI]: 5.2-15.6). We also found that the net reproduction number fell below unity 15 days (95% CI: 11-21 days) after the arrival of the index case. Hence, our study illustrates the time window for successful containment of EVD outbreaks caused by infected air travelers.

An alternate graft for staged flexor tendon reconstruction.

We describe the novel use of semitendinosus as a tendon graft for 2-stage flexor digitorum profundus (FDP) reconstruction. To our knowledge, this is the first reported use of a hamstring tendon graft in this setting. The FDP of two digits were reconstructed in a 30 year-old male who presented 18 years after the original injury. The semitendinosus was chosen as a graft as the traditional grafts were deemed inappropriate. The result of the operation is convincing, and we suggest the semitendinosus tendon to be considered an option for FDP reconstruction.

Investigation of a large community-based outbreak of hepatitis B infection in the United Kingdom.

We describe the largest outbreak of hepatitis B virus infection reported to date in the UK. Between July 2001 and December 2005, 237 cases were identified in Avon, South West England. The likely route of transmission was injecting drug use in 44% (104/237) and heterosexual intercourse in 30% (71/237) of cases. A case-control study in injectors showed that injecting crack cocaine [adjusted odds ratio (aOR) 23·8, 95% confidence interval (CI) 3·04-186, P<0·001] and sharing injecting paraphernalia in the year before diagnosis (aOR 16·67, 95% CI 1·78-100, P=0·010) were strongly associated with acute hepatitis B. In non-IDUs number of sexual partners and lack of consistent condom use were high compared to a national sample. We describe the control measures implemented in response to the outbreak. This outbreak has highlighted the problems associated with the low uptake from the national hepatitis B vaccination policy which targets high-risk groups, the difficulties of identifying those at risk of acquiring hepatitis B infection through heterosexual sex, and injecting crack cocaine as a risk factor for hepatitis B.

Chitosan-tripolyphosphate submicron particles as the carrier of entrapped rutin.

Chitosan (CH)-tripolyphosphate (TPP) submicron particles were formed as carriers of entrapped rutin, and the release properties characterized using simulated gastric juices and fluids of the small intestine. Particle size, charge and entrapment efficiencies were investigated as a function of the CH:TPP molar ratio (2.0:1.0-5.0:1.0). Size was found to decrease from ~814 nm for the 2.0:1:0 mass ratio to ~528 nm for the ratios between 2.5:1.0 and 4.0:1.0, and then again to ~322 nm for the 5:0:1.0 mass ratio, whereas all particles carried a positive surface charge, increasing from +21 to +59 mV as the ratio increased from 2.0:1.0 to 5.0:1.0. The percent entrapment was found to rise from 3.68% to 57.6% as the ratios increased from 2.0:1:0 to 4.0:1:0, before reaching a plateau. Submicron particles (4.0:1.0 mass ratio only) were found to retain rutin in simulated gastric fluids, whereas in conditions which simulated fluids from the small intestine, only 20% of the entrapped rutin was released and 80% remained absorbed to the CH:TPP carriers. Such particles have applications for the delivery of phenolics in food and natural health products.

Dependence of liquid crystal morphology on phospholipid hydrocarbon length.

The liquid crystal morphologies of symmetrical diacy phosphatidylcholine liposomes examined in this research study were found to be dependent on saturated hydrocarbon chain length. Both powder X-ray diffraction and synchrotron mid-IR spectromicroscopy indicate that phosphatidylcholines with short hydrocarbon tails (i.e. ten and twelve carbons) are more likely to form unilamellar liposomes while those with long hydrocarbon tails (i.e. eighteen and twenty carbons) are more likely to form multilamellar liposomes. Hydrocarbon chain lengths of fourteen and sixteen represent a transitional zone between these two liquid crystal morphologies. The FTIR spectra where a shoulder develops on the peak at wavenumber 1750 cm(-1) particularly highlights the change in the packing of adjacent molecules in the transitional zone.

Prioritising prevention strategies for patients in antiretroviral treatment programmes in resource-limited settings.

Expanded access to antiretroviral therapy (ART) offers opportunities to strengthen HIV prevention in resource-limited settings. We invited 27 ART programmes from urban settings in Africa, Asia and South America to participate in a survey, with the aim to examine what preventive services had been integrated in ART programmes. Twenty-two programmes participated; eight (36%) from South Africa, two from Brazil, two from Zambia and one each from Argentina, India, Thailand, Botswana, Ivory Coast, Malawi, Morocco, Uganda and Zimbabwe and one occupational programme of a brewery company included five countries (Nigeria, Republic of Congo, Democratic Republic of Congo, Rwanda and Burundi). Twenty-one sites (96%) provided health education and social support, and 18 (82%) provided HIV testing and counselling. All sites encouraged disclosure of HIV infection to spouses and partners, but only 11 (50%) had a protocol for partner notification. Twenty-one sites (96%) supplied male condoms, seven (32%) female condoms and 20 (91%) provided prophylactic ART for the prevention of mother-to child transmission. Seven sites (33%) regularly screened for sexually transmitted infections (STI). Twelve sites (55%) were involved in activities aimed at women or adolescents, and 10 sites (46%) in activities aimed at serodiscordant couples. Stigma and discrimination, gender roles and funding constraints were perceived as the main obstacles to effective prevention in ART programmes. We conclude that preventive services in ART programmes in lower income countries focus on health education and the provision of social support and male condoms. Strategies that might be equally or more important in this setting, including partner notification, prompt diagnosis and treatment of STI and reduction of stigma in the community, have not been implemented widely.

Gender inequity in the provision of care for hip disease: population-based cross-sectional study.

OBJECTIVES: To examine gender differences along the care pathway to total hip replacement. METHODS: We conducted a population-based cross-sectional study of 26,046 individuals aged 35 years and over in Avon and Somerset. Participants completed a questionnaire asking about care provision at five milestones on the pathway to total hip replacement. Those reporting hip disease were invited to a clinical examination. We estimated odds ratios (ORs) [95% confidence intervals (CI)] for provision of care to women compared with men. RESULTS: 3169 people reported hip pain, 2018 were invited for clinical examination, and 1405 attended (69.6%). After adjustment for age and disease severity, women were less likely than men to have consulted their general practitioner (OR 0.78, 95%-CI 0.61-1.00), as likely as men to have received drug therapy for hip pain in the previous year (OR 0.96, 95%-CI 0.74-1.24), but less likely to have been referred to specialist care (OR 0.53, 95%-CI 0.40-0.70), to have consulted an orthopaedic surgeon (OR 0.50, 95%-CI 0.32-0.78), or to be on a waiting list for total hip replacement (OR 0.41, 95%-CI 0.20-0.87). Differences remained in the 746 people who had sought care from their general practitioner, and after adjustment for willingness and fitness for surgery. CONCLUSIONS: There are gender inequalities in provision of care for hip disease in England, which are not fully accounted for by gender differences in care seeking and treatment preferences. Differences in referral to specialist care by general practitioners might unwittingly contribute to this inequity. Accurate information about availability, benefits and risks of hip replacement for providers and patients, and continuing education to ensure that clinicians interpret and correct patients' assumptions could help reduce inequalities.

Predicting the population impact of chlamydia screening programmes: comparative mathematical modelling study.

BACKGROUND: Published individual-based, dynamic sexual network modelling studies reach different conclusions about the population impact of screening for Chlamydia trachomatis. The objective of this study was to conduct a direct comparison of the effect of organised chlamydia screening in different models. METHODS: Three models simulating population-level sexual behaviour, chlamydia transmission, screening and partner notification were used. Parameters describing a hypothetical annual opportunistic screening program in 16-24 year olds were standardised, whereas other parameters from the three original studies were retained. Model predictions of the change in chlamydia prevalence were compared under a range of scenarios. RESULTS: Initial overall chlamydia prevalence rates were similar in women but not men and there were age and sex-specific differences between models. The number of screening tests carried out was comparable in all models but there were large differences in the predicted impact of screening. After 10 years of screening, the predicted reduction in chlamydia prevalence in women aged 16-44 years ranged from 4% to 85%. Screening men and women had a greater impact than screening women alone in all models. There were marked differences between models in assumptions about treatment seeking and sexual behaviour before the start of the screening intervention. CONCLUSIONS: Future models of chlamydia transmission should be fitted to both incidence and prevalence data. This meta-modelling study provides essential information for explaining differences between published studies and increasing the utility of individual-based chlamydia transmission models for policy making.

Changing epidemiology of HIV anonymous testing in Switzerland for 1996-2006.

QUESTIONS UNDER STUDY: To assess whether the prevalence of HIV positive tests in clients at five anonymous testing sites in Switzerland had increased since the end of the 1990s, and ascertain whether there had been any concurrent change in the proportions of associated risk factors. METHODS: Baseline characteristics were analysed, by groups of years, over the eleven consecutive years of data collected from the testing sites. Numbers of HIV positive tests were presented as prevalence/1000 tests performed within each category. Multivariable analyses, stratified by African nationality and risk group of heterosexuals or men who have sex with men (MSM), were done controlling simultaneously for a series of variables. Odds ratios (ORs) were reported together with their 95% confidence intervals (CI). P values were calculated from likelihood ratio tests. RESULTS: There was an increase in the prevalence of positive tests in African heterosexuals between 1996-1999 and 2004-2006, rising from 54.2 to 86.4/1000 and from 5.6 to 25.2/1000 in females and males respectively. The proportion of MSM who knew that one or more of their sexual partners was infected with HIV increased from 2% to 17% and the proportion who reported having more than five sexual partners in the preceding two years increased from 44% to 51%. CONCLUSIONS: Surveillance data from anonymous testing sites continue to provide useful information on the changing epidemiology of HIV and thus inform public health strategies against HIV.

Real-time quantitative PCR to determine chlamydial load in men and women in a community setting.

We used a PCR method to quantify the loads of Chlamydia trachomatis organisms in self-collected urine and vulvovaginal swab (VVS) samples from 93 women and 30 men participating in the Chlamydia Screening Studies Project, a community-based study of individuals not seeking health care. For women, self-collected VVS had a higher mean chlamydial load (10,405 organisms/ml; 95% confidence interval [95% CI], 5,167 to 21,163 organisms/ml) than did first-void urines (FVU) (503 organisms/ml; 95% CI, 250 to 1,022 organisms/ml; P < 0.001). Chlamydial loads in female and male self-collected FVU specimens were similar (P = 0.634). The mean chlamydial load in FVU specimens decreased with increasing age in females and males. There was no strong statistical evidence of differences in chlamydial load in repeat male and female FVU specimens taken when patients attended for treatment a median of 23.5 (range, 14 to 62) and 28 (range, 13 to 132) days later, respectively, or in VVS taken a median of 35 (range, 14 to 217) days later. In this study, chlamydial load values for infected persons in the community who were not seeking treatment were lower than those published in other studies involving symptomatic patients attending clinical settings. This might have implications for estimates of the infectiousness of chlamydia. The results of this study provide a scientific rationale for preferring VVS to FVU specimens from women.

Pectoralis major interposition flap: a new technique for treatment of severe peri-ductal mastitis.

BACKGROUND: Peri-ductal mastitis is an uncommon benign disorder of the major lactiferous ductal system of the female breast. It can be a very difficult problem to treat and may cause significant patient morbidity. We describe a new technique, involving use of the pectoralis major muscle flap, for treating recurrent sub-areolar abscess refractory to standard surgical treatment. METHOD: Three patients who underwent this new technique for severe refractory peri-ductal mastitis at Calvary Hospital, Canberra are presented. RESULTS: These patients who had recurrent peri-ductal mastitis with abscess and fistula formation on a monthly basis despite numerous courses of antibiotics and surgical procedures experienced no further recurrences following pectoralis major interposition flap surgery at 42, 32 and 22 months follow-up respectively. CONCLUSION: This new technique may provide an opportunity to control these otherwise difficult to treat cases of severe recurrent peri-ductal mastitis where standard surgical methods have failed.

Impact of comorbidity on headache-related disability.

OBJECTIVE: To assess and compare the extent to which comorbid conditions explain the role disability associated with migraine and other severe headaches. METHODS: A probability sample of US adults (n = 5,692) was interviewed. Presence of headaches, other chronic pain conditions, and chronic physical conditions was assessed in a structured interview administered by trained interviewers. Diagnostic criteria for migraine were based on the International Headache Society classification. Mental disorders were ascertained with the Composite International Diagnostic Interview that collected diagnostic criteria according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition. Role disability was assessed with World Health Organization Disability Assessment Schedule questions about days out of role and days with impaired role functioning. RESULTS: Eighty-three percent of migraineurs and 79% of persons with other severe types of headache had some form of comorbidity. Compared with headache-free subjects, migraineurs were at significantly increased risk for mental disorders (odds ratio [OR] 3.1), other pain conditions (OR 3.3), and physical diseases (OR 2.1). Compared with headache-free subjects, persons with nonmigraine headache were also at significantly increased risk for mental disorders (OR 2.0), other pain conditions (OR 3.5), and physical diseases (OR 1.7). Migraineurs experienced role disability on 25.2% of the last 30 days compared with 17.6% of the days for persons with nonmigraine headaches and 9.7% of the days for persons without headache. Comorbid conditions explained 65% of the role disability associated with migraine and all of the role disability associated with other severe headaches. CONCLUSIONS: Comorbidity is an important factor in understanding disability among persons with headache.

Wheeze and asthma prevalence and related health-service use in white and south Asian pre-schoolchildren in the United Kingdom.

BACKGROUND: Epidemiological data for south Asian children in the United Kingdom are contradictory, showing a lower prevalence of wheeze, but a higher rate of medical consultations and admissions for asthma compared with white children. These studies have not distinguished different asthma phenotypes or controlled for varying environmental exposures. OBJECTIVE: To compare the prevalence of wheeze and related health-service use in south Asian and white pre-schoolchildren in the United Kingdom, taking into account wheeze phenotype (viral and multiple wheeze) and environmental exposures. METHODS: A postal questionnaire was completed by parents of a population-based sample of 4366 white and 1714 south Asian children aged 1-4 years in Leicestershire, UK. Children were classified as having viral wheeze or multiple trigger wheeze. RESULTS: The prevalence of current wheeze was 35.6% in white and 25.5% in south Asian 1-year-olds (P<0.001), and 21.9% and 20.9%, respectively, in children aged 2-4 years. Odds ratios (ORs) (95% confidence interval) for multiple wheeze and for viral wheeze, comparing south Asian with white children, were 2.21 (1.19-4.09) and 1.43 (0.77-2.65) in 2-4-year-olds after controlling for socio-economic conditions, environmental exposures and family history. In 1-year-olds, the respective ORs for multiple and viral wheeze were 0.66 (0.47-0.92) and 0.81 (0.64-1.03). Reported GP consultation rates for wheeze and hospital admissions were greater in south Asian children aged 2-4 years, even after adjustment for severity, but the use of inhaled corticosteroids was lower. CONCLUSIONS: South Asian 2-4-year-olds are more likely than white children to have multiple wheeze (a condition with many features of chronic atopic asthma), after taking into account ethnic differences in exposure to some environmental agents. Undertreatment with inhaled corticosteroids might partly explain their greater use of health services.

Sex differences in the transmission of migraine.

Consistent evidence demonstrates that migraine is far more common in women than in men, but the explanations for this preponderance have not been systematically evaluated. We examined whether the female preponderance is attributable to genetic factors using data from a controlled family study which included 260 probands and their 1232 first-degree adult relatives. We found that although the risk of migraine was three times greater among the relatives of probands with migraine compared with controls, there was no differential risk of migraine among the relatives of male vs. female probands with migraine. Taking these data together with other family studies, we conclude that the increased risk of migraine in females is likely to result from increased exposure to non-familial endogenous or exogenous risk factors for migraine that lower the threshold for expression of migraine in women.

Epidemiological, social, diagnostic and economic evaluation of population screening for genital chlamydial infection.

OBJECTIVES: To investigate epidemiological, social, diagnostic and economic aspects of chlamydia screening in non-genitourinary medicine settings. METHODS: Linked studies around a cross-sectional population-based survey of adult men and women invited to collect urine and (for women) vulvovaginal swab specimens at home and mail these to a laboratory for testing for Chlamydia trachomatis. Specimens were used in laboratory evaluations of an amplified enzyme immunoassay (PCE EIA) and two nucleic acid amplification tests [Cobas polymerase chain reaction (PCR), Becton Dickinson strand displacement amplification (SDA)]. Chlamydia-positive cases and two negative controls completed a risk factor questionnaire. Chlamydia-positive cases were invited into a randomised controlled trial of partner notification strategies. Samples of individuals testing negative completed psychological questionnaires before and after screening. In-depth interviews were conducted at all stages of screening. Chlamydia transmission and cost-effectiveness of screening were investigated in a transmission dynamic model. SETTING AND PARTICIPANTS: General population in the Bristol and Birmingham areas of England. In total, 19,773 women and men aged 16-39 years were randomly selected from 27 general practice lists. RESULTS: Screening invitations reached 73% (14,382/19,773). Uptake (4731 participants), weighted for sampling, was 39.5% (95% CI 37.7, 40.8%) in women and 29.5% (95% CI 28.0, 31.0%) in men aged 16-39 years. Chlamydia prevalence (219 positive results) in 16-24 year olds was 6.2% (95% CI 4.9, 7.8%) in women and 5.3% (95% CI 4.4, 6.3%) in men. The case-control study did not identify any additional factors that would help target screening. Screening did not adversely affect anxiety, depression or self-esteem. Participants welcomed the convenience and privacy of home-sampling. The relative sensitivity of PCR on male urine specimens was 100% (95% CI 89.1, 100%). The combined relative sensitivities of PCR and SDA using female urine and vulvovaginal swabs were 91.8% (86.1, 95.7, 134/146) and 97.3% (93.1, 99.2%, 142/146). A total of 140 people (74% of eligible) participated in the randomised trial. Compared with referral to a genitourinary medicine clinic, partner notification by practice nurses resulted in 12.4% (95% CI -3.7, 28.6%) more patients with at least one partner treated and 22.0% (95% CI 6.1, 37.8%) more patients with all partners treated. The health service and patients costs (2005 prices) of home-based postal chlamydia screening were 21.47 pounds (95% CI 19.91 pounds, 25.99) per screening invitation and 28.56 pounds (95% CI 22.10 pounds, 30.43) per accepted offer. Preliminary modelling found an incremental cost-effectiveness ratio (2003 prices) comparing screening men and women annually to no screening in the base case of 27,000 pounds/major outcome averted at 8 years. If estimated screening uptake and pelvic inflammatory disease incidence were increased, the cost-effectiveness ratio fell to 3700 pounds/major outcome averted. CONCLUSIONS: Proactive screening for chlamydia in women and men using home-collected specimens was feasible and acceptable. Chlamydia prevalence rates in men and women in the general population are similar. Nucleic acid amplification tests can be used on first-catch urine specimens and vulvovaginal swabs. The administrative costs of proactive screening were similar to those for opportunistic screening. Using empirical estimates of screening uptake and incidence of complications, screening was not cost-effective.

Asthma in young south Asian women living in the United Kingdom: the importance of early life.

BACKGROUND: Studies of immigrants suggest that the environment during fetal life and duration of residence in the host country might influence the development of asthma. Little is known about the importance of the timing of the exposure in the host country and whether migrants might be especially vulnerable in certain age windows. OBJECTIVE: We compared the reported prevalence of asthma between young white and south Asian women in the United Kingdom, and investigated associations with country of birth and age at immigration. METHODS: A questionnaire on atopic disorders was posted to 2380 south Asian and 5796 white young mothers randomly sampled in Leicestershire. Data on ethnicity were also available from maternity records. Data were analysed using multivariable logistic regression and a propensity score approach. Results The reported prevalence of asthma was 10.9% in south Asian and 21.8% in white women. South Asian women who migrated to the United Kingdom aged 5 years or older reported less asthma (6.5%) than those born in the United Kingdom or who migrated before age 5 (16.0%), with an adjusted odds ratio of 0.38 [95% Confidence Interval 0.23-0.64, P<0.001]. For those who migrated aged over 5 years, the prevalence did not alter with the duration of residence in the United Kingdom. Current exposure to common environmental risk factors had relatively little effect on prevalence estimates. CONCLUSION: These data from a large population-based study support the hypothesis that early life environmental factors influence the risk of adult asthma.

Screening for Chlamydia trachomatis: a systematic review of the economic evaluations and modelling.

OBJECTIVE: To review systematically and critically, evidence used to derive estimates of costs and cost effectiveness of chlamydia screening. METHODS: Systematic review. A search of 11 electronic bibliographic databases from the earliest date available to August 2004 using keywords including chlamydia, pelvic inflammatory disease, economic evaluation, and cost. We included studies of chlamydia screening in males and/or females over 14 years, including studies of diagnostic tests, contact tracing, and treatment as part of a screening programme. Outcomes included cases of chlamydia identified and major outcomes averted. We assessed methodological quality and the modelling approach used. RESULTS: Of 713 identified papers we included 57 formal economic evaluations and two cost studies. Most studies found chlamydia screening to be cost effective, partner notification to be an effective adjunct, and testing with nucleic acid amplification tests, and treatment with azithromycin to be cost effective. Methodological problems limited the validity of these findings: most studies used static models that are inappropriate for infectious diseases; restricted outcomes were used as a basis for policy recommendations; and high estimates of the probability of chlamydia associated complications might have overestimated cost effectiveness. Two high quality dynamic modelling studies found opportunistic screening to be cost effective but poor reporting or uncertainty about complication rates make interpretation difficult. CONCLUSION: The inappropriate use of static models to study interventions to prevent a communicable disease means that uncertainty remains about whether chlamydia screening programmes are cost effective or not. The results of this review can be used by health service managers in the allocation of resources, and health economists and other researchers who are considering further research in this area.