title: The Role of Healthy Lifestyle in the Implementation of Regressing Suboptimal Health Status among College Students in China: A Nested Case-Control Study.
abstract: Suboptimal health status (SHS) is the intermediate health state between health and disease, it is medically undiagnosed and is also termed functional somatic syndrome. Although its clinical manifestations are complicated and various, SHS has not reached the disease status. Unhealthy lifestyle is associated with many chronic diseases and mortality. In accordance with the impact of lifestyle on health, it is intriguing to determine the association between unhealthy lifestyle and SHS risk.
  
  
  
  We conducted a nested case-control study among healthy Chinese college students from March 2012 to September 2013, which was nested in a prospective cohort of 5676 students. We performed 1:1 incidence density sampling with matched controls for birth year, sex, grade, specialty and individual character. SHS was evaluated using the medical examination report and Sub-health Measurement Scale V1.0 (SHMS V1.0). Exposure was defined as an unhealthy lifestyle per the frequency of six behavioral dimensions from the Health-promoting Lifestyle Profile (HPLP-II).
  
  
  
  We matched 543 cases of SHS (42.66%) in a cohort of 1273 students during the 1.5 years mean follow-up time with controls. A significant difference (t = 9.79, p < 0.001) and a reduction in HPLP-II total score was present at 1.5 years follow-up (135.93 ± 17.65) compared to baseline (144.48 ± 18.66). A level-response effect was recorded with an increase of the total HPLP-II (every dimension was correlated with a decreased SHS risk). Compared to respondents with the least exposure (excellent level), those reporting a general HPLP-II level were approximately 2.3 times more likely to develop SHS (odd ratio = 2.333, 95% CI = 1.471 to 3.700); and those with less HPLP-II level (good level) were approximately 1.6 times more likely (1.644, 1.119-2.414) to develop SHS (p < 0.05). Our data indicated that unhealthy lifestyle behavior with respect to behavioral dimensions significantly affected SHS likelihood. Further analyses revealed a marked increase (average increased 14.73 points) in lifestyle level among those SHS regression to health after 1.5 years, with respect to the HPLP-II behavioral dimensions, in addition to the total score (t = -15.34, p < 0.001).
  
  
  
  SHS is highly attributable to unhealthy lifestyles, and the Int. J. Environ. Res. Public Health 2017, 14, 240 2 of 17 mitigation of modifiable lifestyle risk factors may lead to SHS regression. Increased efforts to modify unhealthy lifestyles are necessary to prevent SHS.
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. jieyu@smu.edu.cn.
authors.forename: Jieyu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Traditional Chinese Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan 250014, Shandong, China. xhjlyh@126.com.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Xiang
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. 13427550499@163.com.
authors.forename: Pingping
authors.initials: P
authors.lastname: Jiang
authors.affiliation: Department of Traditional Chinese Medicine, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou 510170, Guangdong, China. yulinfimmu@126.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Yu
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. niuniu_jing@126.com.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Jing
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. leephialf@126.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Li
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. a2278197a@163.com.
authors.forename: Shengwei
authors.initials: S
authors.lastname: Wu
authors.affiliation: Centre for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China. 13480405@life.hkbu.edu.hk.
authors.forename: Xiuqiong
authors.initials: X
authors.lastname: Fu
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. siyecao2015@163.com.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Centre for Cancer and Inflammation Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong 999077, China. hykwan@hkbu.edu.hk.
authors.forename: Hiuyee
authors.initials: H
authors.lastname: Kwan
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. luoren2014@126.com.
authors.forename: Ren
authors.initials: R
authors.lastname: Luo
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. zhaoxs0609@163.com.
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Zhao
authors.affiliation: School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong, China. sunxiaomin198001@163.com.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Sun
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D002681:China / Q000453:epidemiology; D005260:Female; D006293:Health Promotion; D006304:Health Status; D006801:Humans; D008019:Life Style; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D040242:Risk Reduction Behavior; D013334:Students; D014495:Universities; D055815:Young Adult
keywords: SHS regression; health-promoting; nested case-control; suboptimal health status (SHS); unhealthy lifestyle