Obesity and overweight in relation to liver disease mortality in men: 38 year follow-up of the original Whitehall study

Shape of BMI-Mortality Risk Associations: Reverse Causality and Heterogeneity in a Representative Cohort of US Adults

OBJECTIVE

This study examines BMI-mortality associations and evaluates strategies intended to limit reverse causality. Heterogeneity in BMI-mortality risk associations across subgroups and causes of death is explored.

METHODS

A cohort of 654,382 adults from the US National Health Interview Survey was constructed. Associations between unit BMI levels and mortality were estimated using Cox proportional hazards models, including and excluding the first 5 years of follow-up, with and without controls for smoking or preexisting conditions, and including and excluding ever-smokers and individuals with preexisting conditions. Stratified analyses by individual characteristics were performed.

RESULTS

Addressing reverse causality led to reduced risk of mortality among those with low BMI levels (<18 kg/m² ). Excluding ever-smokers and individuals with preexisting conditions further led to increased risk among those with high BMI levels (between 33 kg/m² and >40 kg/m² ) and lowered the estimated nadir risk from 27 kg/m² to 23 kg/m² . After excluding ever-smokers and individuals with preexisting conditions, limiting the analysis to >5 years of follow-up produced no substantive changes. Heterogeneous results were observed across individual characteristics, particularly age and causes of death.

CONCLUSIONS

The exclusion of smokers and individuals with preexisting conditions alters the BMI-mortality risk association and results in a somewhat lower range of BMI with minimum mortality risk.

Body mass index in early pregnancy and future risk of severe liver disease: a population-based cohort study

BACKGROUND

In young men, high body mass index (BMI) has been linked to liver disease later in life, but it is unclear if this also applies to women.

AIM

To study the association between BMI early in life and development of liver disease later in life in women.

METHODS

We obtained data on early pregnancy BMI from 1 139 458 Swedish women between 1992 and 2015. National registers were used to ascertain incident severe liver disease, defined as cirrhosis, decompensated liver disease (hepatocellular carcinoma, oesophageal varices, hepatorenal syndrome or hepatic encephalopathy) or liver failure. A Cox regression model was used to investigate associations of BMI with incident severe liver disease adjusting for maternal age, calendar year, country of birth, smoking, civil status and education.

RESULTS

During an average follow-up of 13.8 years, 774 women developed severe liver disease. Compared to women with a low normal BMI (18.5-22.4), an increased risk of severe liver disease was found in women with BMI between 22.5 and 24.9 kg/m² (adjusted hazard ratio [aHR] 1.25, 95% CI 1.04-1.50), 25.0 and 29.9 kg/m² (aHR 1.27, 95% CI 1.05-1.53) and BMI ≥ 30 kg/m² (aHR 1.77, 95% CI 1.40-2.24). When examining BMI as a continuous variable, the aHR increased by 4% per kg/m² (95% CI 1.02-1.05). A diagnosis of diabetes was associated with an increased risk of severe liver disease independent of baseline BMI.

CONCLUSION

A high BMI early in life in women is associated with a dose-dependent, increased risk for future severe liver disease.

Risk of chronic liver disease in post-menopausal women due to body mass index, alcohol and their interaction: a prospective nested cohort study within the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS)

Background

We investigated the risk of chronic liver disease (CLD) due to alcohol consumption and body mass index (BMI) and the effects of their interaction in a prospective cohort study of women recruited to the UKCTOCS trial.

Methods

95,126 post-menopausal women without documented CLD were stratified into 12 groups defined by combinations of BMI (normal, overweight, obese) and alcohol consumption (none, <1–15, 16–20 and ≥21 units/week), and followed for an average of 5.1 years. Hazard ratios (HR) were calculated for incident liver-related events (LRE).

Results

First LREs were reported in 325 (0.34%) participants. Compared to women with normal BMI, HR = 1.44 (95% CI; 1.10–1.87) in the overweight group and HR = 2.25 (95% CI; 1.70–2.97) in the obese group, adjusted for alcohol and potential confounders. Compared to those abstinent from alcohol, HR = 0.70 (95% CI; 0.55–0.88) for <1–15 units/week, 0.93 (95% CI; 0.50–1.73) for 16–20 units/week and 1.82 (95% CI; 0.97–3.39) for ≥21 units/week adjusted for BMI and potential confounders. Compared to women with normal BMI drinking no alcohol, HR for LRE in obese women consuming ≥21 units/week was 2.86 (95% CI; 0.67–12.42), 1.58 (95% CI; 0.96–2.61) for obese women drinking <1–15 units/week and 1.93 (95% CI; 0.66–5.62) in those with normal BMI consuming ≥21 units/week after adjustment for potential confounders. We found no significant interaction between BMI and alcohol.

Conclusion

High BMI and alcohol consumption and abstinence are risk factors for CLD in post-menopausal women. However, BMI and alcohol do not demonstrate significant interaction in this group.

Trial registration

UKCTOCS is registered as an International Standard Randomised Controlled Trial, number ISRCTN22488978. Registered 06/04/2000.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4518-y) contains supplementary material, which is available to authorized users.

Excess body weight and the risk of primary liver cancer: an updated meta-analysis of prospective studies

AIMS

To provide a quantitative assessment of the association between excess body weight (EBW) and the risk of primary liver cancer (PLC), we performed an updated meta-analysis of prospective observational studies.

METHODS

We searched PUBMED and EMBASE for studies of body mass index and the risk of PLC published through 15 th September 2011. Summary relative risks (SRRs) with their corresponding 95% confidence intervals (CIs) were calculated using a random-effects model. The meta-regression and stratified methods were used to examine heterogeneity across studies.

RESULTS

A total of 26 prospective studies, including 25,337 PLC cases, were included in this analysis. Overall, excess body weight (EBW: body mass index (BMI) ≥ 25 kg/m2) and obesity (BMI ≥ 30 kg/m2) were associated with an increased risk of PLC, with significant heterogeneity (EBW: SRRs 1.48, 95% CIs 1.31-1.67, P(h)<0.001, I2=83.6%; Obesity: SRRs 1.83, 95% CIs 1.59-2.11, P(h)<0.001, I2=75.0%). Subgroup analyses revealed that the positive associations were independent of geographic locations, alcohol consumption, history of diabetes or infections with hepatitis B (HBV) and/or hepatitis C virus (HCV). Obese males had a higher risk of PLC than obese females did (P=0.027). A stronger risk of PLC with EBW was observed for patients with HCV (but not HBV) infection or cirrhosis compared with the general population.

CONCLUSIONS

Findings from this meta-analysis strongly support that EBW or obesity is associated with an increased risk of PLC in both males and females.

Prevention of overweight and obesity: how effective is the current public health approach

Obesity is a public health problem that has become epidemic worldwide. Substantial literature has emerged to show that overweight and obesity are major causes of co-morbidities, including type II diabetes, cardiovascular diseases, various cancers and other health problems, which can lead to further morbidity and mortality. The related health care costs are also substantial. Therefore, a public health approach to develop population-based strategies for the prevention of excess weight gain is of great importance. However, public health intervention programs have had limited success in tackling the rising prevalence of obesity. This paper reviews the definition of overweight and obesity and the variations with age and ethnicity; health consequences and factors contributing to the development of obesity; and critically reviews the effectiveness of current public health strategies for risk factor reduction and obesity prevention.

Walking pace, leisure time physical activity, and resting heart rate in relation to disease-specific mortality in London: 40 years follow-up of the original Whitehall study. An update of our work with professor Jerry N. Morris (1910-2009)

PURPOSE

To examine the association of leisure time physical activity, walking pace and resting heart rate with disease-specific mortality in a prospective cohort study by reporting updated analyses of an earlier report we produced with the British epidemiologist, Jerry N. Morris (1910-2009).

METHODS

In the original Whitehall study, 19,019 male, nonindustrial, London-based government employees, aged from 40 to 69 years in 1967 and 1970, participated in a medical examination during which data on leisure time physical activity (N = 6715), self-rated walking pace (N = 6729), and resting heart rate (N = 1183) were collected. Cox proportional hazards analyses were used to estimate hazard ratios for the relation between these exposures and disease-specific mortality.

RESULTS

In models adjusted for a range of covariates including socioeconomic status, smoking, and obesity, high resting heart rate was associated with a modestly elevated rate of mortality from all causes (hazard ratio; 95% confidence interval: tertile 3 vs. tertile 1: 1.17; 0.99, 1.37 p[trend]: 0.07) and respiratory disease (1.69; 1.04, 2.76 p[trend]: 0.03). Of the two markers of physical activity, walking pace was inversely related to mortality ascribed to all causes (slow vs. high walking pace 1.71; 1.53, 1.91 p[trend]: <0.001]), coronary heart disease (2.03; 1.68, 2.47 p[trend]: <0.001), and total cancers (1.25; 0.98, 1.59 p[trend]: 0.04). The corresponding associations for leisure time activity were typically weaker. For other mortality endpoints-respiratory disease (walking pace: 1.96; 1.48, 2.60 p[trend]: <0.001]), hematopoietic cancer (walking pace: 1.36; 0.52, 3.51 p[trend]: 0.03), stomach cancer (inactive versus active leisure time: 1.53; 0.88, 2.64 p[trend]: 0.04), and rectal cancer (walking pace: 4.85; 1.70, 13.8 p[trend]: 0.007)-individual activity indices revealed effects, but not both.

CONCLUSIONS

Higher levels of physical activity indexed by the various markers herein appeared to confer protection against a range of mortality outcomes.

Obesity, overweight and liver disease in the Midspan prospective cohort studies

OBJECTIVES

To analyse the relationship between body mass index (BMI) and liver disease in men and women.

DESIGN

The Midspan prospective cohort studies.

PARTICIPANTS

The three studies were: Main study, screened in 1965-1968, workplaces across Scotland, the general population of the island of Tiree and mainland relatives; Collaborative study, conducted from 1970 to 1973, 27 workplaces in Glasgow, Clydebank and Grangemouth; Renfrew/Paisley general population study, screened in 1972-1976. After exclusions there were 16 522 men and 10 216 women, grouped by BMI into under/normal weight (< 25 kg m(-2)), overweight (25 to < 30 kg m(-2)) and obese (>or=30 kg m(-2)).

MEASUREMENTS

Relative rates (RRs) of liver disease mortality, subdivided into liver cancer and all other liver disease, by BMI category and per s.d. increase in BMI, followed-up to end 2007. RRs of liver disease from any diagnosis on the death certificate, hospital discharge records or cancer registrations (Collaborative and Renfrew/Paisley studies only 13 027 men and 9328 women). Analyses adjusted for age and study, then other confounders.

RESULTS

In total, 146 men (0.9%) and 61 women (0.6%) died of liver disease as main cause. There were strong associations of BMI with liver disease mortality in men (RR per s.d. increase in BMI=1.41 (95% confidence interval 1.21-1.65)). Obese men had more than three times the rate of liver disease mortality than under/normal weight men. Adjustment for other risk factors had very little effect. No substantial or robust associations were observed in women. In all, 325 men (2.5%) and 155 women (1.7%) had liver disease established from any source. Similar positive associations were observed for men, and there was evidence of a relationship in women.

CONCLUSIONS

BMI is related to liver disease, although not to liver disease mortality in women. The current rise in overweight and obesity may lead to a continuing epidemic of liver disease.

Effect of body mass index and alcohol consumption on liver disease: analysis of data from two prospective cohort studies

OBJECTIVE

To investigate whether alcohol consumption and raised body mass index (BMI) act together to increase risk of liver disease.

DESIGN

Analysis of data from prospective cohort studies.

SETTING

Scotland.

PARTICIPANTS

Data were from two of the Midspan prospective cohort studies (9559 men): "Main" study 1965-8, participants from workplaces across central belt of Scotland, population of island of Tiree, and mainland relatives, and "Collaborative" study, 1970-3, participants from 27 workplaces in Glasgow, Clydebank, and Grangemouth. Follow-up was to 31 December 2007 (median 29 years, range 0.13-42). We divided participants into nine groups based on measures of body mass index (BMI) (underweight/normal weight <25, overweight 25 to <30, and obese >or=30) and alcohol consumption (none, 1-14, and >or=15 units per week).

MAIN OUTCOME MEASURES

Liver disease morbidity and mortality.

RESULTS

80 (0.8%) men died with liver disease as the main cause and 146 (1.5%) with liver disease as any cause. In the Collaborative study, 196 men (3.3%) had liver disease defined by a death, admission, or cancer registration. BMI and alcohol consumption were strongly associated with liver disease mortality in analyses adjusted for other confounders (P=0.001 and P<0.0001 respectively). Drinkers of 15 or more units per week in any BMI category and obese drinkers had raised relative rates for all definitions of liver disease, compared with underweight/normal weight non-drinkers. Drinkers of 15 or more units per week had adjusted relative rates for liver disease mortality of 3.16 (95% confidence interval 1.28 to 7.8) for underweight/normal weight men, 7.01 (3.02 to 16.3) for overweight, and 18.9 (6.84 to 52.4) for obese men. The relative rate for obese men who consumed 1-14 units per week was 5.3 (1.36 to 20.7). The relative excess risk due to interaction between BMI and alcohol consumption was 5.58 (1.09 to 10.1); synergy index=2.89 (1.29 to 6.47).

CONCLUSIONS

Raised BMI and alcohol consumption are both related to liver disease, with evidence of a supra-additive interaction between the two. The occurrence of both factors in the same populations should inform health promotion and public health policies.

Prevention of overweight and obesity: how effective is the current public health approach

Obesity is a public health problem that has become epidemic worldwide. Substantial literature has emerged to show that overweight and obesity are major causes of co-morbidities, including type II diabetes, cardiovascular diseases, various cancers and other health problems, which can lead to further morbidity and mortality. The related health care costs are also substantial. Therefore, a public health approach to develop population-based strategies for the prevention of excess weight gain is of great importance. However, public health intervention programs have had limited success in tackling the rising prevalence of obesity. This paper reviews the definition of overweight and obesity and the variations with age and ethnicity; health consequences and factors contributing to the development of obesity; and critically reviews the effectiveness of current public health strategies for risk factor reduction and obesity prevention.

Obesity and liver cancer mortality in Asia: The Asia Pacific Cohort Studies Collaboration

While obesity is associated with liver cancer in studies from western societies, the paucity of data from Asia limits insights into its aetiological role in this population. We examined the relationship between body mass index (BMI) and liver cancer mortality using data from the Asia Pacific Cohort Studies Collaboration. In 309,203 Asian study members, 4 years of follow-up gave rise to 11,135 deaths from all causes, 420 of which were ascribed to liver cancer. BMI, whether categorised according to current guidelines for Asian groups or World Health Organisation recommendations, was not associated with liver cancer in any of our analyses.

[Nonalcoholic fatty liver disease: 30 years research changed NASH]

Since the first description of nonalcoholic steatohepatitis (NASH) in 1980, much progress has been made towards its individualisation as a liver disease with potentially serious consequences. The identification of insulin resistance as a major determinant of steatogenesis and possibly of liver disease progression helped to identify a cause of this condition, which was amenable to therapeutic intervention and prompted screening for liver injury in patients with metabolic risk factors. The demonstration that steatohepatitis can coexist with other liver diseases with a detrimental effect on liver fibrosis helped this condition to be recognized as an independent hepatic disease no longer depending on exclusion of other chronic liver conditions. The robust increase in liver-related mortality, the fact that cirrhosis is a frequent and independent cause of death, as well as the significant decrease in overall mortality clearly showed the potential for severity of steatohepatitis. The data showing that steatohepatitis worsens insulin resistance and increases the risk for cardiovascular events and mortality forged the concept of extrahepatic complications of fat. Future research should focus on devising non-invasive strategies for screening of patients at risk, on understanding the natural history and risk factors of cirrhosis and hepatic carcinogenesis, and on optimizing therapeutic strategies integrating diet and lifestyle changes with targeted pharmacological agents.