Original Article
International Journal of Obesity advance online publication 15 April 2008; doi: 10.1038/ijo.2008.57
Actigraphic sleep duration and fragmentation are related to obesity in the elderly: the Rotterdam Study
J F van den Berg1,2, A Knvistingh Neven2, J H M Tulen3, A Hofman1, J C M Witteman1, H M E Miedema4 and H Tiemeier1,5
- 1Department of Epidemiology and Biostatistics, Erasmus Medical Center, Rotterdam, The Netherlands
- 2Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands
- 3Department of Psychiatry, Erasmus Medical Center, Rotterdam, The Netherlands
- 4TNO Built Environment and Geosciences, Netherlands Organisation for Applied Scientific Research TNO, Delft, The Netherlands
- 5Department of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, The Netherlands
Correspondence: Dr H Tiemeier, Department of Epidemiology and Biostatistics, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands. E-mail: h.tiemeier@erasmusmc.nl
Received 27 November 2007; Revised 5 March 2008; Accepted 11 March 2008; Published online 15 April 2008.
Abstract
Objective:
The epidemiological evidence for the association between sleep duration and obesity in the elderly is inconsistent and has not been investigated with objective measures. Furthermore, the role of sleep fragmentation in this relationship is unknown. Our aim was to investigate the association of sleep measures with body mass index (BMI) and obesity in a normal elderly population.
Design:
Cross-sectional study.
Subjects:
A total of 983 community-dwelling elderly (mean age 68.4
6.9 years, range, 57–97).
Measurements:
Weight and height were measured, and sleep duration and fragmentation were assessed with on average six nights of actigraphy.
Results:
A quadratic model adequately described the association between continuous measures of sleep duration and BMI. Actigraphic sleep duration had a significant U-shaped relationship with BMI (
of quadratic term=0.30, 95% confidence interval (CI): 0.08, 0.52). Both short sleepers (<5 h: OR, 2.76 (95% CI: 1.38, 5.49), 5 to <6 h: OR, 1.97 (95% CI: 1.26, 3.08)) and long sleepers (
8 h: OR, 2.93 (95% CI: 1.39, 6.16)) were more likely to be obese, compared to participants who slept 7 to <8 h. BMI increased with 0.59 kg m-2 per standard deviation of sleep fragmentation (95% CI: 0.34, 0.84). After adjustment for sleep fragmentation, the association between short sleep and obesity was no longer significant. Exclusion of participants with probable sleep apnea only marginally changed these associations. Self-reported habitual sleep duration was not associated with BMI or obesity.
Conclusions:
Sleep duration, as measured with actigraphy, had a U-shaped relationship with BMI and obesity in an elderly population. A highly fragmented sleep is associated with a higher BMI and a higher risk of obesity, and may explain why short sleep is related to obesity. To preclude bias that can be introduced by self-report measures of sleep duration, using multiple measures of sleep parameters is recommended in future research.
Keywords:
body mass index, sleep duration, sleep fragmentation, actigraphy, elderly
