Obesity and use of acute hospital services in participants of the Renfrew/Paisley study

Hospital length of stay and healthcare costs among African American women due to obesity and diabetic conditions in United States: A model for correlation studies comparing ethnicity, co-morbidities and hospital resources

Objective

To examine obesity and diabetes associations with United States hospital use and healthcare costs for African American women, to explore the relationship between co-morbidities of interest (obesity and diabetes) and hospital resources [length of stay (LOS) and costs].

Methods

A retrospective, correlation, quantitative analysis for lengths of hospital stay and cost among adult African American women categorized according to their weight status with type 2 diabetes. Healthcare Cost and Utilization Project (HCUP) data which contains the Nationwide Inpatient Sample was used. Focused on 803,163 African American, female inpatients between the ages of 21 and 55 in the United States from 2008 to 2010. Researcher explored the relationship between individual health factors of interest (obesity and diabetes) and the effects on hospital LOS and healthcare costs. All statistical analysis will be performed using Stata v12. All inferential tests will be two-sided and will utilize a 95% significance level. Two separate multiple regressions will be used.

Results

A total of 758,874 records were retained for analysis. The patients in the weighted population ranged in age from 21 to 55 years. The patient LOS ranged from 0 to 333 days. The patients had approximately 2 procedures on average, and presented with approximately 3 chronic conditions on average. The total charges (Cost) ranged from 106 to over 1 million US dollars. The size and direction of the relationship between LOS, healthcare costs and the independent variables of diabetes and obesity suggests that both LOS and health care cost decreased for African American female patients with diabetes or obesity. There is a statistically significant relationship between at least one of the individual health factors of interest (obesity and diabetes) and hospital LOS (F = 13,394.00, P < 0.0005, R ²  = 0.440) and hospital costs (F = 10,171.23, P < 0.0005, R ²  = 0.502).

Conclusions

There is evidence of racial and ethnic disparities in health care quality in hospital treatment of African American patients. After accounting for social determinants and insurance statuses, African Americans may receive lower-quality care than the population at large. African Americans are admitted to the hospital, but services and LOS are shorter than the general population partially due to disparities in evaluating and offering treatment.

Obesity and emergency care in the French CONSTANCES cohort

Context

Obese patients are raising specific questions in emergency care such as equipment issues or urgent procedures. Even though obesity prevalence and subsequent health expenditure are increasing worldwide, there is scarce literature about their specific resource utilization of Emergency Departments (ED). These few studies do not take into account both socio-economic situation and comorbidities which are well-known factors influencing healthcare use. Our objective was to assess the emergency care resource utilization of obese individuals (Body Mass Index (BMI) ≥ 30kg.m^-2) compared to normal-weight individuals taking into account comorbidities and social-economic situations.

Methods

The French CONSTANCES epidemiologic cohort is a randomly selected sample of French adults. Participants data are linked to the National Health Insurance Database collecting all medical acts. The rate of ED visits of obese (and each obesity class) and normal-weight participants were compared considering confounding factors (comorbidities, various socio-economic data). The primary endpoint was to have visited the ED between 2010 and 2013. Sex-separated analysis and multivariate logistic regression models were performed and adjusted odds-ratios [OR] (95% Confidence Intervals [CI]) were calculated.

Results

We included 21,035 normal-weight and 5,003 obese participants. Obese participants visited the ED more often than normal-weight participants (men: 30.5% vs. 26.7%; women: 30.3% vs. 24.4%, P<0.001). Obese participants presented more comorbidities and a lower socio-economic situation than normal-weight participants. After adjustment, obese participants had a higher risk of visiting ED (men: OR = 1.18; 95% CI: 1.04–1.33; and women: OR = 1.36; 95% CI: 1.22–1.52), with a higher risk for class III participants (BMI ≥ 40 kg.m^-2) (men: OR = 2.18; CI 95%: 1.32–3.63; and women: OR = 1.85; 95% CI: 1.38–2.49).

Conclusion

Obese individuals have a higher level of emergency care resource utilization than normal-weight individuals and it increases with severe obesity. Further studies are needed to better understand their healthcare pathways leading to EDs.

Feasibility, effectiveness and cost-effectiveness of a telephone-based weight loss program delivered via a hospital outpatient setting

Engaging patients in a group-based weight loss program is a challenge for the acute-care hospital outpatient setting. To evaluate the feasibility, effectiveness and cost-effectiveness of a telephone-based weight loss service and an existing face-to-face, group-based service a non-randomised, two-arm feasibility trial was used. Patients who declined a two-month existing outpatient group-based program were offered a six-month research-based telephone program. Outcomes were assessed at baseline, two months (both groups) and six months (telephone program only) using paired t tests and linear regression models. Cost per healthy life year gained was calculated for both programs. The telephone program achieved significant weight loss (-4.1 ± 5.0 %; p = 0.001) for completers (n = 35; 57 % of enrolees) at six months. Compared to the group-based program (n = 33 completers; 66 %), the telephone program was associated with greater weight loss (mean difference [95%CI] -2.0 % [-3.4, -0.6]; p = 0.007) at two months. The cost per healthy life year gained was $33,000 and $85,000, for the telephone and group program, respectively. Telephone-delivered weight management services may be effective and cost-effective within an acute-care hospital setting, likely more so than usual (group-based) care.

Clinical outcomes for the obese hospital inpatient: An observational study

OBJECTIVES

The prevalence of obesity presents a burden for Australian health care. The aim of this study was to determine whether severely obese hospital inpatients have worse outcomes.

METHODS

This is an observational cohort study, using data from all adult patients admitted to hospital for all elective and emergency admissions of patients aged over 18 years to two large Australian urban hospitals. We measured their length of stay, intensive care unit admission rate, intensive care unit length of stay, mortality and readmission rates within 28 days of discharge and compared these outcomes in the severely obese and non-severely obese subjects using t-test or chi-square test as appropriate.

RESULTS

Between February 2008 and February 2012, 120,872 were admitted to hospital 193,800 times; 2701 patients were identified as severely obese (2.23%) and 118,171 patients were non-severely obese. If admitted as an emergency, severely obese patients have worse outcomes and consume more resources than other patients. These outcomes are still worse, but less so, if the obese patient is admitted as an elective patient suggesting that anticipation of any obesity-specific problems can have a beneficial effect.

CONCLUSION

Upon admission or discharge of severely obese hospital inpatients, health care plans should be even more carefully laid than usual to reduce the risk of readmission.

Continuing to challenge practice to be evidence based

Practice habits continue in clinical practice despite the availability of research and other forms of evidence that should be used to guide critical care practice interventions. This article is based on a presentation at the 2014 National Teaching Institute of the American Association of Critical-Care Nurses. The article is part of a series of articles that challenge critical care nurses to examine the evidence guiding nursing practice interventions. Four common practice interventions are reviewed: (1) weight-based medication administration, (2) chest tube patency maintenance, (3) daily interruption of sedation, and (4) use of chest physiotherapy in children. For weight-based administration of medication, the patient's actual weight should be measured, rather than using an estimate. The therapeutic effectiveness and dosages of medications used in obese patients must be critically evaluated. Maintaining patency of chest tubes does not require stripping and milking, which probably do more harm than good. Daily interruption of sedation and judicious use of sedatives are appropriate in most patients receiving mechanical ventilation. Traditional chest physiotherapy does not help children with pneumonia, bronchiolitis, or asthma and does not prevent atelectasis after extubation. Critical care nurses are challenged to evaluate their individual practice and to adopt current evidence-based practice interventions into their daily practice.

Obesity and the Emergency Short Stay Unit

OBJECTIVES

To evaluate the health service requirements of obese patients admitted to an Emergency Short Stay Unit (ESSU) and specifically compare length of stay (LOS), failure of ESSU management, and rates of investigations and allied health interventions among obese and non-obese patients.

METHODS

A prospective cohort study, using convenience sampling was conducted. The body mass index (BMI) of participants was calculated and those with a BMI of ⩾30 were allocated to the obese group, and those that had a BMI of <30 to the non-obese group. Data collected included demographics, admission diagnosis, time and date of ESSU admission and discharge, discharge disposition, radiological investigations, and referrals made to allied health personnel during ESSU admission.

RESULTS

There were 262 patients that were recruited sub-grouped into 127 (48.5%) obese participants and 135 (51.5%) non-obese participants with similar sex and diagnostic category distributions. The mean LOS in ESSU was similar - 11.5h (95% CI: 9.9-13.1) for obese patients and, 10.2h (95% CI: 8.8-11.6) for non-obese patients (p=0.21). Failure rates of ESSU management, defined as inpatient admission to hospital, were also similar with 29 (22.8%) obese patients admitted to hospital compared to 25 (18.5%) non-obese patients (p=0.39). Plain X-ray requests were significantly higher among obese patients (71.6 vs 53.3%; p=0.002), as was the rate of allied health interventions (p=0.001).

CONCLUSION

There was no significant difference in inpatient admission rates or LOS between obese and non-obese patients managed in the ESSU. Provisions for increased rate of investigations and allied health interventions for obese patients may facilitate timely assessment and disposition from ESSU.

Predicting admissions and time spent in hospital over a decade in a population-based record linkage study: the EPIC-Norfolk cohort

OBJECTIVE

To quantify hospital use in a general population over 10 years follow-up and to examine related factors in a general population-based cohort.

DESIGN

A prospective population-based study of men and women.

SETTING

Norfolk, UK.

PARTICIPANTS

11,228 men and 13,786 women aged 40-79 years in 1993-1997 followed between 1999 and 2009.

MAIN OUTCOMES MEASURES

Number of hospital admissions and total bed days for individuals over a 10-year follow-up period identified using record linkage; five categories for admissions (from zero to highest ≥ 7) and hospital bed days (from zero to highest ≥ 20 nights).

RESULTS

Over a period of 10 years, 18,179 (72.7%) study participants had at least one admission to hospital, 13.8% with 7 or more admissions and 19.9% with 20 or more nights in hospital. In logistic regression models with outcome ≥ 7 admissions, low education level OR 1.14 (1.05 to 1.24), age OR per 10-year increase 1.75 (1.67 to 1.82), male sex OR 1.32 (1.22 to 1.42), manual social class 1.22 (1.13 to 1.32), current cigarette smoker OR 1.53 (1.37 to 1.71) and body mass index >30 kg/m² OR 1.41 (1.28 to 1.56) all independently predicted the outcome with p<0.0001. Results were similar for those with ≥ 20 hospital bed days. A risk score constructed using male sex, manual social class, no educational qualifications; current smoker and body mass index >30 kg/m², estimated percentages of the cohort in the categories of admission numbers and hospital bed days in stratified age bands with twofold to threefold differences in future hospital use between those with high-risk and low-risk scores.

CONCLUSIONS

The future probability of cumulative hospital admissions and bed days appears independently related to a range of simple demographic and behavioural indicators. The strongest of these is increasing age with high body mass index and smoking having similar magnitudes for predicting risk of future hospital usage.

The impact of excess body weight at the hospital frontline

Quantification of disease burden by deaths or years lived with disability is a useful indicator as it informs prevention by accounting for health loss but it does not reflect the needs for health services. An alternative indicator is to quantify the impact of a risk factor on health care utilization. In an article published in BMC Medicine, Reeves and colleagues describe the relationship between body mass index in 1.2 million women (England) and hospital admission rates. The main finding was that around one in eight hospital admissions was attributable to overweight or obesity, translating to around 420,000 extra hospital admissions, and two million extra days spent in hospital, annually. These findings reinforce the evidence that excess body weight is associated with extensive healthcare utilization and emphasize the need to scale-up and speed-up research if global problems, such as obesity, are to be tackled with due alacrity.Please see related research: http://www.biomedcentral.com/1741-7015/12/45.

Hospital admissions in relation to body mass index in UK women: a prospective cohort study

BACKGROUND

Adiposity is associated with many adverse health outcomes but little direct evidence exists about its impact on the use of health care services. We aim to describe the relationship between body mass index (BMI) and rates of hospital admission in middle-aged UK women.

METHODS

Among 1,251,619 Million Women Study participants, 50- to 64-years old at entry into the study, routine data on hospital admissions were used to estimate hospitalization rates according to BMI after standardization for age, region of recruitment, socioeconomic status, reproductive history, smoking status, hormonal therapy use and alcohol intake. Proportional hazards models were used to estimate adjusted relative risks of hospitalization separately for 25 common types of admission.

RESULTS

During an average of 9.2 years follow-up, there were 2,834,016 incident hospital admissions. In women with BMIs (in kg/m2) of <22.5, 22.5 to <25, 25 to <30, 30 to <35 and 35+ standardized admission rates (and 95% confidence intervals (CIs)) per woman over a 10-year period were 2.4 (2.4 to 2.4), 2.4 (2.3 to 2.4), 2.6 (2.6 to 2.6), 3.0 (3.0 to 3.0) and 3.5 (3.4 to 3.5), respectively (P-value for heterogeneity <0.001). The relative increase in admission rates per 5 kg/m2 increase in BMI was 1.12 (1.12 to 1.13). This relationship did not vary materially by age. Corresponding average durations of stay (in days) per hospital visit within the same categories of BMI were: 3.1 (3.1 to 3.2), 2.8 (2.7 to 2.8), 2.9 (2.9 to 2.9), 3.2 (3.1 to 3.2) and 3.8 (3.7 to 3.8), respectively (P <0.001).Significant increases in the risk of admission with increasing BMI were observed for 19 of the 25 types of hospital admission considered. BMI was most strongly associated with admissions with diabetes, knee-replacement, gallbladder disease and venous thromboembolism, but marked associations were found with many other common categories of admission including cataracts, carpal tunnel syndrome and diverticulitis.

CONCLUSIONS

Among women 50- to 84-years old in England, around one in eight hospital admissions are likely to be attributable to overweight or obesity, translating to around 420,000 extra hospital admissions and two million extra days spent in hospital, annually.

Overweight, obesity and related conditions: a cross-sectional study of adult inpatients at a Norwegian hospital

Background

Overweight, obesity and associated conditions are major public health concerns in Norway. The prevalence of overweight and obesity in the general population in Norway is increasing, but there are limited data on how the situation is in hospitals. This study aimed to find the prevalence of overweight and obesity, and explore the associations of overweight, obesity and its related medical conditions in an adult in-patient sample at specified somatic and psychiatric departments at St. Olavs Hospital, Trondheim.

Results

A total of 497 patients participated. The mean BMI for the total sample at screening was 25.4 kg/m². The prevalence of overweight and obesity was 45.1%. There was a higher association of overweight and obesity among patients aged 40–59 years (OR: 1.7) compared to those being younger. There was no significant difference between the somatic and the psychiatric samples. In the somatic sample overweight and obesity was associated with obesity-related conditions for both genders (OR: 2.0 and 2.1, respectively), when adjusted for age.

Conclusion

The substantial prevalence of overweight and obese patients may pose a threat to future hospital services. To further address the burden of overweight and obesity in hospitals, we need more knowledge about consequences of length of stay, use of resources and overall cost.

A real-world, multicenter assessment of drugs requiring weight-based calculations in overweight, adult critically ill patients

Prescribing appropriate doses of drugs requiring weight-based dosing is challenging in overweight patients due to a lack of data. With 68% of the US population considered overweight and these patients being at an increased risk for hospitalization, clinicians need guidance on dosing weight-based drugs. The purpose of this study was to identify “real-world” dose ranges of high-risk medications administered via continuous infusion requiring weight-based dosing and determine the reasons for dosing changes (ineffectiveness or adverse drug reactions). A prospective, multicenter, observational study was conducted in four intensive care units at three institutions. A total of 857 medication orders representing 11 different high-risk medications in 173 patients were reviewed. It was noted that dosing did not increase in proportion to weight classification. Overall, 14 adverse drug reactions occurred in nine patients with more in overweight patients (9 of 14). A total of 75% of orders were discontinued due to ineffectiveness in groups with higher body mass indexes. Ineffectiveness leads to dosing adjustments resulting in the opportunity for medication errors. Also, the frequent dosing changes further demonstrate our lack of knowledge of appropriate dosing for this population. Given the medications' increased propensity to cause harm, institutions should aggressively monitor these medications in overweight patients.

Obesity significantly increases the difficulty of patient management in the emergency department

OBJECTIVE

To determine which aspects of ED management are adversely affected by patient obesity, to determine the level of obesity above which management is made more difficult and to make recommendations on how these effects might be mitigated.

METHODS

This was a cross-sectional survey of patients and the staff caring for them in a single ED. Doctors, nurses and radiographers managing consecutive patients, during a range of enrolment periods, completed a self-administered questionnaire. Each was asked to record how the level of their patient's obesity increased the difficulty of specific management items, using a Likert scale. Staff also provided recommendations to mitigate the effects of obesity for each patient, if applicable. For each management item, body mass index (BMI) and management difficulty were correlated (Spearman's rank correlation).

RESULTS

Seven hundred and fifty patients and their ED carers were enrolled. Patient BMI was positively correlated with all aspects of ED clinical management examined (correlation coefficient range 0.28-0.57, P < 0.001). BMI most strongly correlated with difficulty in finding anatomical landmarks, venous pressure measurement, physical examination, patient positioning and procedures generally, especially cannulation and venipuncture (coefficient > 0.5, P < 0.001). Doctors reported more difficulties than nurses and radiographers. Generally, management difficulty did not increase until the BMI was in the obese or morbidly obese range. Most staff recommendations related to issues of patient mobility including equipment, staffing and bariatric devices.

CONCLUSION

Patient obesity significantly increases the difficulty of ED patient management. Staff recommendations to mitigate these effects were few but may inform changes in ED practice.

The relationship between body mass index and number of days spent in hospital in Scotland

In most countries in the Western world, more than 50% of adults are overweight or obese putting them at increased risk of hypertension, type 2 diabetes, coronary heart disease, stroke and other chronic disorders. It is not clear what impact increasing prevalence of over-weight and obesity has on hospital admissions. The objective of this study was to examine the relationship between body mass index (BMI) and number of days spent in hospital. The study was designed as a retrospective and prospective cohort study using nationally representative Health Survey data linked to NHS hospital admissions data. The study was set in Scotland. The participants were a nationally representative sample of 6968 (45%) men and 8700 (55%) women, of 16-74 years of age, living in private households whose BMI was recorded in the 1995 and 1998 Scottish Health Surveys. The outcome measure was the number of days spent in hospital between 1981 and 2004. The results showed that the proportion of participants in both normal weight (BMI 20-24.9 kg/m(2)) and over-weight (BMI 25-29.9 kg/m(2)) categories was 37%, with 21% in the obese (BMI ≥30 kg/m(2)) and 5% in the under-weight (BMI <20 kg/m(2)) categories. The median number of days spent in hospital between 1981 and 2004 was six. The odds ratios (95% confidence intervals) for spending above the median numbers of days in hospital adjusted for age, sex, socioeconomic status and behavioural factors (i.e. smoking, alcohol drinking and physical activity) were 1.29 (1.06-1.56) for the <20 kg/m(2) group, 1.00 (0.91-1.11) for the 25-29.9 kg/m(2) group and 1.24 (1.10-1.38) for the ≥30 kg/m(2) group compared with the 20-24.9 kg/m(2) group. In conclusion, extremes of BMI category identified at a single point in time are associated with spending above the median number of days in hospital over a 20-year period after adjusting for demographic, behavioural and socioeconomic exposures.

Association between TNF-α promoter G-308A and G-238A polymorphisms and obesity

Tumor necrosis factor-α (TNF-α), an adipokine, is produced in adipocytes, and the elevation of its levels has been linked to obesity and insulin resistance in some population. In this study the relationship between TNF-α promoter gene polymorphism and obesity in an Iranian population has been studied. Subjects were randomly selected from Tehran Cohort Lipid and Glucose Study. Adult participants placed in three groups according to their body mass index (BMI): BMI < 25, 25 ≤ BMI < 30, BMI ≥ 30 and under-18 subjects placed in two groups, under 85th percentile BMI and above 85th percentile. Finally, 244 persons were selected for G-308A and G-238A polymorphisms analysis. The FBS, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride, cholesterol levels and blood pressure and HOMA of all subjects were measured. The polymorphism −308 and −238 were revealed by restriction fragment length polymorphism (RFLP; NCOI and MSPI) after the promoter site was amplified by PCR. The allele frequency of TNF-α polymorphism was in the Hardy–Weinberg equilibrium. There was no relation between BMI and the frequency of this allele. The fact that there is no association between G-308A and G-238A TNF-α promoter polymorphisms and obesity probably shows that it is not an important risk factor for obesity and consequently for cardiovascular disease.

Trimming the fat: identification of risk factors associated with obesity in a pediatric emergency department

OBJECTIVE

The purpose of this study was to assess which knowledge deficits and dietary habits in an urban pediatric emergency department (ED) population are risk factors for obesity.

METHODS

This cross-sectional study in an urban pediatric ED used a modified version of the Diet and Health Knowledge Survey, an in-person interview questionnaire, to collect data on demographics, dietary knowledge, and practices. All patients aged 2 to 17 years were enrolled in the study over a 4-month period. Subjects were excluded if they were in extremis, pregnant, incarcerated, institutionalized, considered an emancipated minor, or consumed only a modified consistency diet.

RESULTS

One hundred seventy-nine subjects were enrolled in this study. Based on body mass index, the prevalence of obesity in our study population was 24%. Parents with obese children answered a mean of 62.9% (95% confidence interval, 60.4%-65.5%) of knowledge questions correctly, whereas all others scored 60.3% (95% confidence interval, 58.3%-62.3%) correctly. Based on the univariate analysis, 10 predictors met inclusion criteria into logistic regression analysis: screen time (P = 0.03), race (P = 0.08), sex (P = 0.04), parental education (P = 0.08), parental estimation that child is overweight (P < 0.0001), parental estimation that child is underweight (P = 0.003), trimming fat from meat (P = 0.06), soft-drink consumption (P = 0.03), exercise (P = 0.07), and chip consumption (P = 0.04). In a multivariate analysis, only male sex, regularly trimming fat from meat, and parental assessment of obesity were independently associated with obesity.

CONCLUSIONS

Knowledge deficiencies regarding healthy nutrition among parents in an urban pediatric ED population were not significantly associated with having obese children; however, specific habits were. Emergency physicians may provide a valuable role in identification and brief behavioral intervention in high-risk populations during the current epidemic of childhood obesity.

Population attributable risk for diabetes associated with excess weight in Tehranian adults: a population-based cohort study

Background

Little evidence exists regarding the magnitude of contribution of excess weight to diabetes in the Middle East countries. This study aimed at quantification of the impact of overweight and obesity on the incidence of type 2 diabetes mellitus (T2DM) at a population level in Tehran, Iran.

Methods

Using data of a population-based short-term cohort study in Iran, which began in 1997 with 3.6-year follow-up, we calculated the adjusted odds ratios (OR) and population attributable risks (PAR) of developing T2DM, i.e. the proportion of diabetes that could have been avoided had overweight and/or obesity not been present in the population.

Results

Of the 4728 subjects studied, aged ≥ 20 years, during the 3.6-year follow-up period, 3.8% (n = 182) developed T2DM. This proportion was 1.4%, 3.6%, and 7.8% for the normal, overweight, and obese subjects, respectively. When compared to normal BMI, the adjusted ORs for incident diabetes were 1.76 [95% confidence interval (CI) 1.07 to 2.89] for overweight and 3.54 (95% CI 2.16 to 5.79) for obesity. The PARs adjusted for family history of diabetes, age, triglycerides, systolic blood pressure was 23.3% for overweight and 37.1% for obesity. These figures were 7.8% and 26.6% for men and 35.3% and 48.3% for women, respectively.

Conclusion

Incident T2DM is mainly attributable to excess weight, significantly more so in Tehranian women than men. Nonetheless, the contribution of excess weight in developing T2DM was lower in our short-term study than that reported in long-term periods. This probably reflects the significant role of other risk factors of T2DM in a short-term follow-up. Hence, prevention of excess weight probably should be considered as a major strategy for reducing incidence of T2DM; the contribution of other risk factors in developing T2DM in short-term period deserve to be studied and be taken into account.

Body mass index in middle life and future risk of hospital admission for psychoses or depression: findings from the Renfrew/Paisley study

BACKGROUND

There is evidence that greater body mass index (BMI) protects against depression, schizophrenia and suicide. However, there is a need for prospective studies.

METHOD

We examined the association of BMI with future hospital admissions for psychoses or depression/anxiety disorders in a large prospective study of 7036 men and 8327 women. Weight and height were measured at baseline (1972-76) when participants were aged 45-64. Follow-up was for a median of 29 years.

RESULTS

Greater BMI and obesity were associated with a reduced risk of hospital admission for psychoses and depression/anxiety in both genders, with the magnitude of these associations being the same for males and females. With adjustment for age, sex, smoking and social class, a 1 standard deviation (s.d.) greater BMI at baseline was associated with a rate ratio of 0.91 [95% confidence interval (CI) 0.82-1.01] for psychoses and 0.87 (95% CI 0.77-0.98) for depression/anxiety. Further adjustment for baseline psychological distress and total cholesterol did not alter these associations.

CONCLUSIONS

Our findings add to the growing body of evidence that suggests that greater BMI is associated with a reduced risk of major psychiatric outcomes. Long-term follow-up of participants in randomized controlled trials of interventions that effectively result in weight loss and the use of genetic variants that are functionally related to obesity as instrumental variables could help to elucidate whether these associations are causal.