Interventions to enhance testing, linkage to care, and treatment initiation for hepatitis C virus infection: a systematic review and meta-analysis

BACKGROUND

Despite the goal set by WHO to eliminate hepatitis C virus (HCV) as a public health threat, uptake of HCV testing and treatment remains low. To achieve this target, evidence-based interventions are needed to address the barriers to care for people with, or at risk of, HCV infection. We aimed to assess the efficacy of interventions to improve HCV antibody testing, HCV RNA testing, linkage to HCV care, and treatment initiation.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE (PubMed), Scopus, Web of Science, the Cochrane Central Register of Controlled Trials, and PsycINFO without language restrictions for reports published between database inception and July 21, 2020, assessing the following primary outcomes: HCV antibody testing; HCV RNA testing; linkage to HCV care; and direct-acting antiviral treatment initiation. We also searched key conference abstracts. We included randomised and non-randomised studies assessing non-pharmaceutical interventions that included a comparator or control group. Studies were excluded if they enrolled only paediatric populations (aged <18 years) or if they conducted the intervention in a different health-care setting to that of the control or comparator. Authors were contacted to clarify study details and to obtain additional population-level data. Data were extracted from the records identified into a pre-piloted and standardised data extraction form and a random-effects meta-analysis was used to pool the effects of the interventions on study outcomes. This study is registered in PROSPERO, CRD42020178035.

FINDINGS

Of 15 342 unique records identified, 142 were included, which reported on 148 unique studies (47 randomised controlled trials and 101 non-randomised studies). Medical chart reminders, provider education, and point-of-care antibody testing significantly improved at least three study outcomes compared with a comparator or control. Interventions that simplified HCV testing, including dried blood spot testing, point-of-care antibody testing, reflex RNA testing, and opt-out screening, significantly improved testing outcomes compared with a comparator or control. Enhanced patient and provider support through patient education, provider care coordination, and provider education also significantly improved testing outcomes compared with a comparator or control. Integrated care and patient navigation or care coordination significantly improved linkage to care and the uptake of direct-acting antiviral treatment compared with a comparator or control.

INTERPRETATION

Several interventions to improve HCV care that address several key barriers to HCV care were identified. New models of HCV care must be designed and implemented to address the barriers faced by the population of interest. Further high-quality research, including rigorously designed randomised studies, is still needed in key populations.

FUNDING

None.

'Not just one box that you tick off' - Deconstructing the hepatitis C care cascade in the interferon-free direct acting antiviral era from the client perspective

BACKGROUND

To achieve hepatitis C viral (HCV) elimination targets set by the World Health Organisation, pillars of the HCV care cascade are often referenced to track progress. The aim of this qualitative study was to explore the limitations of the care cascade framework through the real-world accounts of 'HCV journeys' among people who inject drugs (PWID), with particular attention to the intersection of PWID agency and structural determinants in the healthcare system.

METHODS

An in-depth analysis was conducted on five case studies to better understand participant experiences 'behind the cascade pillars'. The five case studies were drawn from the ETHOS Engage cohort as exemplars of the real-world complexities of people's HCV cascade journeys. Inclusion criteria for the qualitative study were participant has voluntarily signed the informed consent form, aged ≥18 years, HCV antibody positive by self-report, clients of selected sites participating in the ETHOS Engage cohort, and sufficiently proficient in English to participate in an interview. Thirty-four semi-structured interviews were conducted with participants who had received or had not received HCV treatment to identify barriers and facilitators to HCV care.

RESULTS

Participants 'housed' at the 'HCV RNA diagnosed pillar' (n = 2; Will; Julie) reported withholding their HCV serostatus in certain healthcare settings for fear that disclosure would lead to discriminatory decision-making from their treating physician. among participants who had completed treatment (n = 3; Corey; John; Nora) two reported still being unsure of their HCV status >6 months post-treatment. Ongoing feelings of frustration and shame were expressed in this 'post-cure care pillar' due to a perceived lack of quality care from clinic services and continued uneasiness when discussing drug use and reinfection while receiving opioid agonist treatment (OAT). Both case 'categories' described often tenuous therapeutic relationships with their physicians and recommended task-shifting to nurses and trusted case workers for ongoing care.

CONCLUSION

The care cascade provides a linear, two dimensional snapshot of clinical targets. Our findings illuminate structural barriers not visible behind its 'static' pillars, presenting insights into experiences among PWID otherwise dismissed as 'disengaged' or 'lost to follow-up'.

Non-fatal opioid overdose, naloxone access, and naloxone training among people who recently used opioids or received opioid agonist treatment in Australia: The ETHOS Engage study

BACKGROUND

Overdose is a major cause of morbidity and mortality among people who use opioids. Naloxone can reverse opioid overdoses and can be distributed and administered with minimal training. People with experience of overdose are a key population to target for overdose prevention strategies. This study aims to understand if factors associated with recent non-fatal opioid overdose are the same as factors associated with naloxone access and naloxone training in people who recently used opioids or received opioid agonist treatment (OAT).

METHODS

ETHOS Engage is an observational study of people who inject drugs in Australia. Logistic regression models were used to estimate odds ratios for non-fatal opioid overdose, naloxone access and naloxone training.

RESULTS

Between May 2018-September 2019, 1280 participants who recently used opioids or received OAT were enrolled (62% aged >40 years; 35% female, 80% receiving OAT, 62% injected drugs in the preceding month). Recent opioid overdose (preceding 12 months) was reported by 7% of participants, lifetime naloxone access by 17%, and lifetime naloxone training by 14%. Compared to people receiving OAT with no additional opioid use, recent opioid, benzodiazepine (preceding six months), and hazardous alcohol use was associated with recent opioid overdose (aOR 3.91; 95%CI: 1.68-9.10) and lifetime naloxone access (aOR 2.12; 95%CI 1.29-3.48). Among 91 people who reported recent overdose, 65% had never received take-home naloxone or naloxone training.

CONCLUSIONS

Among people recently using opioids or receiving OAT, benzodiazepine and hazardous alcohol use is associated with non-fatal opioid overdose. Not all factors associated with non-fatal overdose correspond to factors associated with naloxone access. Naloxone access and training is low across all groups. Additional interventions are needed to scale up naloxone provision.

Applying a diffusion of innovations framework to the scale-up of direct-acting antiviral therapies for hepatitis C virus infection: Identified challenges for widespread implementation

BACKGROUND AND AIMS

Interferon-free, direct-acting antivirals (DAAs) for hepatitis C virus (HCV) offer much promise to achieve World Health Organization targets by 2030. However, impediments at the practitioner and health-system level will continue to obstruct the scale-up of DAAs worldwide unless identified and acted upon. Applying a diffusion of innovations framework, the aim of this study was to identify structural factors impacting practitioner experiences of managing HCV treatment.

METHODS

In-depth, semi-structured, telephone interviews took place between September 2018 and April 2019 to investigate barriers and facilitators for engaging in HCV management and DAA therapy amongst general practitioners (GPs) who prescribe opioid agonist therapy and drug and alcohol specialists in Australia. Interviews were transcribed verbatim, de-identified, and coded, and data were analysed with iterative categorisation and thematic analysis using Everett Rogers's diffusion of innovation framework.

RESULTS

amongst 30 participants (12 GPs, 18 drug and alcohol specialists), several structural factors were reported to impede practitioner efforts to deliver optimal HCV care. Two primary themes were explored: contextual factors for the diffusion of DAA therapies, including attempts by participants to shift clinic culture and respond to siloed health structures, and adopter factors. Some participants chose to 'rock the boat' by circumventing clinic protocol and HCV guidelines to treat more clients, effectively shifting adopter categories to become greater advocates in HCV care. Also, while a role for GPs as the 'new adopters' in HCV management was discussed, many participants expressed uncertainty as to how much GPs should become involved in the diffusion of DAA therapies more widely.

CONCLUSIONS

Reducing the global burden of HCV infection will not be possible without the widespread delivery of HCV treatment amongst practitioners. Practitioners and health workers require leadership and resources from health authorities so that the individual and population-level benefits of DAA therapy are realised.

Urban manta rays: potential manta ray nursery habitat along a highly developed Florida coastline

The giant oceanic manta ray Mobula birostris was listed in the US Endangered Species Act as a threatened species in 2018, yet insufficient data exist on manta populations throughout US waters to designate critical habitat. Taxonomic and genetic evidence suggests that manta rays in the Western Atlantic are a separate species (M. cf. birostris) and little is understood about the ecology and life history of this putative species. The juvenile life stage of both M. birostris and M. cf. birostris is particularly understudied. Here, we are the first to describe the characteristics of a manta ray population along a highly developed coastline in southeastern Florida using boat-based surveys and photo identification of individuals. Fifty-nine manta individuals were identified between 2016 and 2019. All males were sexually immature based on clasper development, and 96% of females were classified as immature based on size and absence of mating scars or visible pregnancies. Twenty-five (42%) individuals were observed more than once during the study period and 8 individuals were sighted over multiple years. The occurrence of juveniles, high site fidelity and extended use of the study area by juvenile manta rays suggest that southeastern Florida may serve as a nursery habitat. High occurrence of fishing line entanglement (27% of individuals) and vessel strike injury were documented, and rapid wound healing was observed. Future research and conservation efforts will focus on identifying the physical and biological features of the potential nursery habitat and on mitigation of anthropogenic impacts.

Hepatitis C virus testing, liver disease assessment and treatment uptake among people who inject drugs pre- and post-universal access to direct-acting antiviral treatment in Australia: The LiveRLife study

Gaps in hepatitis C virus (HCV) testing, diagnosis, liver disease assessment and treatment uptake among people who inject drugs (PWID) persist. We aimed to describe the cascade of HCV care among PWID in Australia, prior to and following unrestricted access to direct-acting antiviral (DAA) treatment. Participants enrolled in an observational cohort study between 2014 and 2018 provided fingerstick whole-blood samples for dried blood spot, Xpert HCV Viral Load and venepuncture samples. Participants underwent transient elastography and clinical assessment by a nurse or general practitioner. Among 839 participants (mean age 43 years), 66% were male (n = 550), 64% (n = 537) injected drugs in the previous month, and 67% (n = 560) reported currently receiving opioid substitution therapy. Overall, 45% (n = 380) had detectable HCV RNA, of whom 23% (n = 86) received HCV treatment within 12 months of enrolment. HCV treatment uptake increased from 2% in the pre-DAA era to 38% in the DAA era. Significant liver fibrosis (F2-F4) was more common in participants with HCV infection (38%) than those without (19%). Age 50 years or older (aOR, 2.88; 95% CI, 1.18-7.04) and attending a clinical follow-up with nurse (aOR, 3.19; 95% CI, 1.61-6.32) or physician (aOR, 11.83; 95% CI, 4.89-28.59) were associated with HCV treatment uptake. Recent injection drug use and unstable housing were not associated with HCV treatment uptake. HCV treatment uptake among PWID has increased markedly in the DAA era. Evaluation of innovative and simplified models of care is required to further enhance treatment uptake.

Barriers and facilitators to engaging in hepatitis C management and DAA therapy among general practitioners and drug and alcohol specialists-The practitioner experience

BACKGROUND

Since the advent of interferon-free, direct-acting antiviral (DAA) therapies for hepatitis C virus (HCV) infection, prescriber restrictions have been removed worldwide, permitting HCV management outside of hospital-based clinics. To date, there is limited knowledge of the practitioner experience with DAA treatments, particularly among those new to HCV care. The aim of this qualitative study was to investigate barriers and facilitators for HCV management among general practitioners (GPs) who prescribe opioid agonist therapy (OAT) and drug and alcohol specialists.

METHODS

In-depth, semi-structured telephone interviews were conducted between September 2018 and April 2019. Practitioners from across Australia were purposively sampled and questioned on barriers and facilitators to HCV management in their clinic(s). Data were coded and analysed with iterative categorisation and thematical analysis.

RESULTS

Thirty practitioners were interviewed. Participants expressed professional fulfillment in managing HCV care and many benefited from specialist mentorship. Most participants expressed frustration with ongoing implementation barriers, notably, a lack of onsite phlebotomy services and liver disease staging equipment. Poor venous access among persons who inject drugs was elucidated as a major barrier to treatment initiation. Some participants did not receive clinic manager support to engage in HCV care.

CONCLUSION

To achieve HCV targets set by WHO by 2030, practitioners require additional implementation support. As HCV testing remains a barrier to linkage to care, practitioners should be kept well-informed of diagnostic developments. Findings also underscore the importance of initial specialist mentorship with further evidence needed for practitioners based in rural regions.

The removal of DAA restrictions in Europe - One step closer to eliminating HCV as a major public health threat

Of ∼10.2 million people with chronic HCV infection in Europe, 6.7 million live in Eastern Europe, 2.3 million in Western Europe and 1.2 million in Central Europe. HCV transmission continues to occur in parallel with an increasing HCV-related liver disease burden, the result of an ageing population infected during peak HCV epidemics decades earlier. In 2016, the World Health Organization set targets to eliminate HCV infection as a major public health threat by 2030. Across Europe, an estimated 36% of those living with chronic HCV infection have been diagnosed and ∼5% have been treated. A major barrier to enhancing HCV treatment uptake has been restrictions set by payers, including national governments and others, in response to the initially high list prices of direct-acting antiviral (DAA) therapies. The aims of this article are to discuss DAA restrictions in Europe, why DAA restrictions are still in place, what has facilitated the removal of DAA restrictions, and what challenges remain as we attempt to eliminate HCV as a major public health threat in the region by 2030.

Acceptability and preferences of point-of-care finger-stick whole-blood and venepuncture hepatitis C virus testing among people who inject drugs in Australia

BACKGROUND

Uptake of hepatitis C virus (HCV) testing remains inadequate globally. Simplified point-of-care tests should enhance HCV diagnosis and elimination. We aimed to assess the acceptability of finger-stick and venepuncture HCV RNA testing among people who inject drugs (PWID).

METHODS

Participants were enrolled in an observational cohort study with recruitment at 13 sites between June 2016 and February 2018. Capillary whole-blood collected by finger-stick and plasma collected by venepuncture were performed for Xpert^® HCV viral load testing. Participants completed a questionnaire on acceptability of, and preferences for, blood collection methods.

RESULTS

Among 565 participants (mean age, 44 years; 69% male), 64% reported injecting drugs in the last month, and 63% were receiving opioid substitution treatment. Eighty three percent reported that finger-stick testing was very acceptable. Overall, 65% of participants preferred finger-stick over venepuncture testing, with 61% of these preferring to receive results in 60 min. The most common reason for preferring finger-stick over venepuncture testing was it was quick (62%) followed by venous access difficulties (21%). The main reasons for preferring venepuncture over finger-stick testing were that it was quick (61%) and accurate (29%). Females were more likely to prefer finger-stick testing than males (adjusted OR 1.96; 95% CI 1.30, 2.99; p = 0.002). Among people with recent (previous month) injecting drug use, Aboriginal and/or Torres Strait Islander people were less likely than non-Aboriginal people to prefer finger-stick testing (adjusted OR 0.57; 95% CI 0.34, 0.9; p = 0.033).

CONCLUSIONS

Finger-stick whole-blood collection is acceptable to people who inject drugs, with males and Aboriginal and/or Torres Strait Islander people with recent injecting drug use less likely to prefer finger-stick testing. Further research is needed to evaluate interventions integrating simplified point-of-care HCV testing to engage people in care in a single-visit, thereby facilitating HCV treatment scale-up.

The 7th Canadian Symposium on Hepatitis C Virus: “Toward Elimination of HCV: How to Get There”

Hepatitis C virus (HCV) affects more than 268,000 people in Canada. Both the Canadian Institutes of Health Research and the Public Health Agency of Canada recognize the significant impact of HCV-related liver diseases and supported the establishment of a national hepatitis C research network, the Canadian Network on Hepatitis C (CanHepC). Interferon-free direct-acting antiviral regimens lead to more than 95% cure rates in almost all patients with well-tolerated short-course therapy. However, the goal of eliminating HCV in Canada cannot be fully realized until we overcome the financial, geographical, cultural, and social barriers that affect the entire continuum of care from diagnosis and linkage to care through treatment and prevention of new and reinfections. Current practices face difficulties in reversing HCV-induced immunological defects, expanding treatment to neglected communities, combating reinfections and co-infections, and expediting and simplifying the processes of diagnosis and treatment. As part of its knowledge translation mandate, CanHepC has organized the annual Canadian symposium on hepatitis C since 2012. The theme of this year’s symposium, “Toward Elimination of HCV: How to Get There?” focused on identifying the requirements of our therapeutic strategies and health policies for the elimination of HCV in Canada.

Do women with complex alcohol and other drug use histories want women-only residential treatment?

BACKGROUND

Women-only addiction services tend to be provided on a poorly evidenced assumption that women want single-sex treatment. We draw upon women's expectations and experiences of women-only residential rehabilitation to stimulate debate on this issue.

METHODS

Semi-structured interviews were undertaken with 19 women aged 25-44 years [currently in treatment (n = 9), successfully completed treatment (n = 5), left treatment prematurely (n = 5)]. All had histories of physical or sexual abuse, and relapses linked to relationships with men. Interviews were audio-recorded, transcribed verbatim, coded and analysed inductively following Iterative Categorization.

FINDINGS

Women reported routinely that they had been concerned, anxious or scared about entering women-only treatment. They attributed these feelings to previous poor relationships with women, being more accustomed to male company and negative experiences of other women-only residential settings. Few women said that they had wanted women-only treatment, although many became more positive after entering the women-only service. Once in treatment, women often explained that they felt safe, supported, relaxed, understood and able to open up and develop relationships with other female residents. However, they also described tensions, conflicts, mistrust and social distancing that undermined their treatment experiences.

CONCLUSIONS

Women who have complex histories of alcohol and other drug use do not necessarily want or perceive benefit in women-only residential treatment.

CTCF genetic alterations in endometrial carcinoma are pro-tumorigenic

CTCF is a haploinsufficient tumour suppressor gene with diverse normal functions in genome structure and gene regulation. However the mechanism by which CTCF haploinsufficiency contributes to cancer development is not well understood. CTCF is frequently mutated in endometrial cancer. Here we show that most CTCF mutations effectively result in CTCF haploinsufficiency through nonsense-mediated decay of mutant transcripts, or loss-of-function missense mutation. Conversely, we identified a recurrent CTCF mutation K365T, which alters a DNA binding residue, and acts as a gain-of-function mutation enhancing cell survival. CTCF genetic deletion occurs predominantly in poor prognosis serous subtype tumours, and this genetic deletion is associated with poor overall survival. In addition, we have shown that CTCF haploinsufficiency also occurs in poor prognosis endometrial clear cell carcinomas and has some association with endometrial cancer relapse and metastasis. Using shRNA targeting CTCF to recapitulate CTCF haploinsufficiency, we have identified a novel role for CTCF in the regulation of cellular polarity of endometrial glandular epithelium. Overall, we have identified two novel pro-tumorigenic roles (promoting cell survival and altering cell polarity) for genetic alterations of CTCF in endometrial cancer.

Restrictions for reimbursement of direct-acting antiviral treatment for hepatitis C virus infection in Canada: a descriptive study

BACKGROUND

In Canada, interferon-free, direct-acting antiviral hepatitis C virus (HCV) regimens are costly. This presents challenges for universal drug coverage of the estimated 220 000 people with chronic HCV infection nationwide. The study objective was to appraise criteria for reimbursement of 4 HCV direct-acting antivirals in Canada.

METHODS

We reviewed the reimbursement criteria for simeprevir, sofosbuvir, ledipasvir-sofosbuvir and paritaprevir-ritonavir-ombitasvir plus dasabuvir in the 10 provinces and 3 territories. Data were extracted from April 2015 to June 2016. The primary outcomes extracted from health ministerial websites were: 1) minimum fibrosis stage required, 2) drug and alcohol use restrictions, 3) HIV coinfection restrictions and 4) prescriber type restrictions.

RESULTS

Overall, 85%-92% of provinces/territories limited access to patients with moderate fibrosis (Meta-Analysis of Histologic Data in Viral Hepatitis stage F2 or greater, or equivalent). There were no drug and alcohol use restrictions; however, several criteria (e.g., active injection drug use) were left to the discretion of the physician. Quebec did not reimburse simeprevir and sofosbuvir for people coinfected with HIV; no restrictions were found in the remaining jurisdictions. Prescriber type was restricted to specialists in up to 42% of provinces/territories.

INTERPRETATION

This review of criteria of reimbursement of HCV direct-acting antivirals in Canada showed substantial interjurisdictional heterogeneity. The findings could inform health policy and support the development and adoption of a national HCV strategy.

ASCT2/SLC1A5 controls glutamine uptake and tumour growth in triple-negative basal-like breast cancer

Alanine, serine, cysteine-preferring transporter 2 (ASCT2; SLC1A5) mediates uptake of glutamine, a conditionally essential amino acid in rapidly proliferating tumour cells. Uptake of glutamine and subsequent glutaminolysis is critical for activation of the mTORC1 nutrient-sensing pathway, which regulates cell growth and protein translation in cancer cells. This is of particular interest in breast cancer, as glutamine dependence is increased in high-risk breast cancer subtypes. Pharmacological inhibitors of ASCT2-mediated transport significantly reduced glutamine uptake in human breast cancer cell lines, leading to the suppression of mTORC1 signalling, cell growth and cell cycle progression. Notably, these effects were subtype-dependent, with ASCT2 transport critical only for triple-negative (TN) basal-like breast cancer cell growth compared with minimal effects in luminal breast cancer cells. Both stable and inducible shRNA-mediated ASCT2 knockdown confirmed that inhibiting ASCT2 function was sufficient to prevent cellular proliferation and induce rapid cell death in TN basal-like breast cancer cells, but not in luminal cells. Using a bioluminescent orthotopic xenograft mouse model, ASCT2 expression was then shown to be necessary for both successful engraftment and growth of HCC1806 TN breast cancer cells in vivo. Lower tumoral expression of ASCT2 conferred a significant survival advantage in xenografted mice. These responses remained intact in primary breast cancers, where gene expression analysis showed high expression of ASCT2 and glutamine metabolism-related genes, including GLUL and GLS, in a cohort of 90 TN breast cancer patients, as well as correlations with the transcriptional regulators, MYC and ATF4. This study provides preclinical evidence for the feasibility of novel therapies exploiting ASCT2 transporter activity in breast cancer, particularly in the high-risk basal-like subgroup of TN breast cancer where there is not only high expression of ASCT2, but also a marked reliance on its activity for sustained cellular proliferation.

Liver disease knowledge and acceptability of non-invasive liver fibrosis assessment among people who inject drugs in the drug and alcohol setting: The LiveRLife Study

BACKGROUND

The aim of this study was to assess factors associated with baseline knowledge of HCV and liver disease, acceptability of transient elastography (TE) assessment (FibroScan(®)), and willingness and intent to receive HCV treatment among persons with a history of injection drug use participating in a liver health promotion campaign.

METHODS

The LiveRLife campaign involved three phases: (1) campaign resource development; (2) campaign resource testing; and (3) campaign implementation. Participants were enrolled in an observational cohort study with recruitment at four clinics - one primary health care facility, two OST clinics, and one medically supervised injecting centre - in Australia between May and October 2014. Participants received educational material, nurse clinical assessment, TE assessment, dried blood spot testing, and completed a knowledge survey.

RESULTS

Of 253 participants (mean age 43 years), 68% were male, 71% had injected in the past month, and 75% self-reported as HCV positive. Median knowledge score was 16/23. In adjusted analysis, less than daily injection (AOR 5.01; 95% CI, 2.64-9.51) and no daily injection in the past month (AOR 3.54; 95% CI, 1.80-6.94) were associated with high knowledge (≥16). TE was the most preferred method both pre- (66%) and post-TE (89%) compared to liver biopsy and blood sample. Eighty-eight percent were 'definitely willing' or 'somewhat willing' to receive HCV treatment, and 56% intended to start treatment in the next 12 months. Approximately 68% had no/mild fibrosis (F0/F1, ≥2.5 to ≤7.4kPa), 13% moderate fibrosis (F2, ≥7.5 to ≤9.4kPa), 10% severe fibrosis (F3, ≥9.5 to ≤12.4kPa), and 9% had cirrhosis (F4, ≥12.5kPa).

CONCLUSION

Liver disease and HCV knowledge was moderate. High acceptability of TE by PWID provides strong evidence for the inclusion of TE in HCV-related care, and could help to prioritise HCV treatment for those at greatest risk of liver disease progression.

Slowing down of adult body mass index trend increases in England: a latent class analysis of cross-sectional surveys (1992-2010)

BACKGROUND

The prevalence of excess body weight, commonly measured as body mass index (BMI)≥25 kg m(-2), has increased substantially in many populations worldwide over the past three decades, but the rate of increase has slowed down in some western populations.

OBJECTIVE

We address the hypothesis that the slowing down of BMI trend increases in England reflects a majority sub-population resistant to further BMI elevation.

DESIGN

Pseudo-panel data derived from annual cross-sectional surveys, the Health Surveys for England (1992-2010). Trends in median BMI values were explored using regression models with splines, and gender-specific mixture model (latent class analysis) were fit to take an account of increasing BMI distribution variance with time and identify hidden subgroups within the population.

SUBJECTS

BMI was available for 164 155 adults (men: 76 382; women: 87 773).

RESULTS

Until 2001, the age-adjusted yearly increases in median BMI were 0.140 and 0.139 kg m(-2) for men and women, respectively, decreasing thereafter to 0.073 and 0.055 kg m(-2) (differences between time periods, both P-values<0.0001). The mixture model identified two components--a normal BMI and a high BMI sub-population--the proportions for the latter were 23.5% in men and 33.7% in women. The remaining normal BMI populations were 'resistant' with minimal increases in mean BMI values over time. By age, mean BMI values in the normal BMI sub-population increased greatest between 20 and 34 years for men; for women, the increases were similar throughout age groups (slope differences, P<0.0001).

CONCLUSION

In England, recent slowing down of adult BMI trend increases can be explained by two sub-populations--a high BMI sub-population getting 'fatter' and a majority 'resistant' normal BMI sub-population. These findings support a targeted, rather than a population-wide, policy to tackle the determinants of obesity.