Relationships between chronotype, social jetlag, sleep, obesity and blood pressure in healthy young adults

ABSTRACT

Sleep disturbances, chronotype and social jetlag (SJL) have been associated with increased risks for major chronic diseases that take decades to develop, such as obesity, metabolic syndrome and cardiovascular disease. Potential relationships between poor sleep, chronotype and SJL as they relate to metabolic risk factors for chronic disease have not been extensively investigated. This prospective study examined chronotype, SJL and poor sleep in relation to both obesity and elevated blood pressure among healthy young adults.

SJL and objective sleep measures (total sleep time, sleep onset latency, wake after sleep onset and sleep efficiency) were derived from personal rest/activity monitoring (armband actigraphy) among 390 healthy adults 21–35 years old. Participants wore the device for 6–10 days at 6-month intervals over a 2-year period (n = 1431 repeated observations). Chronotypes were categorized into morning, intermediate and evening groups using repeated measures latent class analysis. Means of SJL and sleep measures among latent chronotype groups were compared using partial F-tests in generalized linear mixed models. Generalized linear mixed models also were used to generate odds ratios (ORs) with 95% confidence intervals (CIs) examining the relationship between repeated measures of chronotype, SJL, sleep and concurrent anthropometric outcome measures (body mass index, percentage of body fat, waist-to-hip ratio, waist-to-height ratio), systolic blood pressure and diastolic blood pressure.

Sleep latency ≥12 min was associated with increased odds of a high waist-to-height ratio (OR = 1.37; CI: 1.03–1.84). Neither chronotype nor SJL was independently associated with anthropometric outcomes or with blood pressure. Relationships between poor sleep and anthropometric outcomes or blood pressure varied by chronotype. Morning types with total sleep time <6 h, sleep efficiency <85% or wake after sleep onset ≥60 min were more likely to have an increased percentage of body fat, waist-to-hip ratio and waist-to-height ratio relative to those with an intermediate chronotype. Similarly, sleep latency ≥12 min was associated with increased odds of elevated systolic blood pressure (OR = 1.90; CI: 1.15–3.16, p_interaction = 0.02) among morning versus intermediate chronotypes. No relationships between poor sleep and obesity or elevated blood pressure were observed among evening chronotypes.

The results from this study among healthy young adults suggest that poor sleep among morning types may be more strongly associated with obesity and elevated blood pressure relative to those with an intermediate (neutral) chronotype. Sleep-related metabolic alterations among different chronotypes warrant further investigation.

KEYWORDS:

• Actigraphy
• body mass index
• chronotype
• repeated measures latent class analysis
• sleep efficiency
• social jetlag

Acknowledgment

The authors thank the study participants and the Energy Balance Study team.

Disclosure statement

J.B.B. was supported by a Dept. of Veterans Affairs Office of Research and Development grant (Merit Award: I01CX001182-01A1). J.R.H. was supported by an Established Investigator Award in Cancer Prevention and Control from the Cancer Training Branch of the National Cancer Institute (K05 CA136975). M.D.W. and J.R.H. were supported by grant number R44DK103377 [N. Shivappa and M.D. Wirth, Multiple PIs] from the National Institute of Diabetes and Digestive and Kidney Diseases. S.D.Y. was supported by an NIH grant (R01HL095799) and a Dept. of Veterans Affairs Office ofResearch and Development grant (Merit Award: 5I01CX000898). S.N.B. serves on the scientific advisory boards of Technogym, Clarity, and Santech. He has received research funding from BodyMedia, Technogym, the U.S. Department of Defense, and the NIH, and he receives book royalties from Human Kinetics. G.A.H. has no disclosures. The Energy Balance Study was funded by an unrestricted grant from Coca-Cola Company. Coca-Cola representatives did not participate in the data analyses, interpretation of the results or manuscript preparation.

Supplementary material

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Additional information

Funding

This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases [R44DK103377]; National Institutes of Health [R01HL095799]; VA Merit [5I01CX000898]; Established Investigator Award in Cancer Prevention and Control from the Cancer Training Branch of the National Cancer Institute [K05 CA136975]; Dept. of Veterans Affairs Office of Research and Development grant [Merit Award: I01CX001182-01A1].