Psychological Medicine

Original Article

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

DEBBIE A. LAWLORa1 c1, CAROLE L. HARTa2, DAVID J. HOLEa2, DAVID GUNNELLa1 and GEORGE DAVEY SMITHa1

a1 Department of Social Medicine, University of Bristol, UK

a2 Public Health and Health Policy, Division of Community Based Sciences, University of Glasgow, Glasgow, UK

ABSTRACT

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.

(Online publication April 04 2007)

Correspondence

c1 *Address for correspondence: Professor D. A. Lawlor, Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, Bristol BS8 2PR, UK. (Email: d.a.lawlor@bristol.ac.uk)

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