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Do worse baseline risk factors explain the association of healthy obesity with increased mortality risk? Whitehall II Study

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journal contribution
posted on 30.07.2018, 14:11 by Will Johnson, Joshua A. Bell, Ellie M. Robson, Tom Norris, Mika Kivimaki, Mark Hamer
Objective: To describe 20-year risk factor trajectories according to initial weight/health status and investigate the extent to which baseline differences explain greater mortality among metabolically healthy obese (MHO) individuals than healthy non-obese individuals. Methods: The sample comprised 6 529 participants in the Whitehall II study who were measured serially between 1991-1994 and 2012-2013. Baseline weight (non-obese or obese; body mass index (BMI) ≥30 kg/m2) and health status (healthy or unhealthy; two or more of hypertension, low high-density lipoprotein cholesterol (HDL-C), high triglycerides, high glucose, and high homeostatic model assessment of insulin resistance (HOMA-IR)) were defined. The relationships of baseline weight/health status with 20-year trajectories summarizing ~25 000 observations of systolic and diastolic blood pressures, HDL-C, triglycerides, glucose, and HOMA-IR were investigated using multilevel models. Relationships of baseline weight/health status with all-cause mortality up until July 2015 were investigated using Cox proportional hazards regression. Results: Trajectories tended to be consistently worse for the MHO group compared to the healthy non-obese group (e.g., glucose by 0.21 (95% CI 0.09, 0.33; p < 0.001) mmol/L at 20-years of follow-up). Consequently, the MHO group had a greater risk of mortality (hazard ratio 2.11 (1.24, 3.58; p = 0.006)) when the referent group comprised a random sample of healthy non-obese individuals. This estimate, however, attenuated (1.34 (0.85, 2.13; p = 0.209)) when the referent group was matched to the MHO group on baseline risk factors. Conclusions: Worse baseline risk factors may explain any difference in mortality risk between obese and non-obese groups both labelled as healthy, further challenging the concept of MHO.

Funding

This work was supported by the UK Medical Research Council (WJ New Investigator Research Grant: MR/P023347/1).

History

School

  • Sport, Exercise and Health Sciences

Published in

International Journal of Obesity

Volume

43

Pages

1578–1589

Citation

JOHNSON, W.O. ... et al., 2018. Do worse baseline risk factors explain the association of healthy obesity with increased mortality risk? Whitehall II Study. International Journal of Obesity, 43, pp.1578-1589.

Publisher

Nature Publishing Group

Version

VoR (Version of Record)

Rights holder

© The authors

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

26/07/2018

Publication date

2018-08-14

Copyright date

2018

Notes

This is an Open Access Article. It is published by Nature under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

ISSN

0307-0565

Language

en

Licence

Exports