title: China suboptimal health cohort study: rationale, design and baseline characteristics.
abstract: Suboptimal health status (SHS) is a physical state between health and disease, characterized by the perception of health complaints, general weakness, chronic fatigue and low energy levels. SHS is proposed by the ancient concept of traditional Chinese medicine (TCM) from the perspective of preservative, predictive and personalized (precision) medicine. We previously created the suboptimal health status questionnaire 25 (SHSQ-25), a novel instrument to measure SHS, validated in various populations. SHSQ-25 thus affords a window of opportunity for early detection and intervention, contributing to the reduction of chronic disease burdens.
  
  
  
  To investigate the causative effect of SHS in non-communicable chronic diseases (NCD), we initiated the China suboptimal health cohort study (COACS), a longitudinal study starting from 2013. Phase I of the study involved a cross-sectional survey aimed at identifying the risk/protective factors associated with SHS; and Phase II: a longitudinal yearly follow-up study investigating how SHS contributes to the incidence and pattern of NCD.
  
  
  
  (1) Cross-sectional survey: in total, 4313 participants (53.8 % women) aged from 18 to 65 years were included in the cohort. The prevalence of SHS was 9.0 % using SHS score of 35 as threshold. Women showed a significantly higher prevalence of SHS (10.6 % in the female vs. 7.2 % in the male, P < 0.001). Risk factors for chronic diseases such as socioeconomic status, marital status, highest education completed, physical activity, salt intake, blood pressure and triglycerides differed significantly between subjects of SHS (SHS score ≥35) and those of ideal health (SHS score <35). (2) Follow up: the primary and secondary outcomes will be monitored from 2015 to 2024.
  
  
  
  The sex-specific difference in prevalence of SHS might partly explain the gender difference of incidence of certain chronic diseases. The COACS will enable a thorough characterization of SHS and establish a cohort that will be used for longitudinal analyses of the interaction between the genetic, lifestyle and environmental factors that contribute to the onset and etiology of targeted chronic diseases. The study together with the designed prospective cohort provides a chance to characterize and evaluate the effect of SHS systemically, and it thus generates an unprecedented opportunity for the early detection and prevention of chronic disease.
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.|Global Health and Genomics, School of Medical and Health Sciences, Edith Cowan University, Perth, 6027, Australia.
authors.forename: Youxin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.|Global Health and Genomics, School of Medical and Health Sciences, Edith Cowan University, Perth, 6027, Australia.
authors.forename: Siqi
authors.initials: S
authors.lastname: Ge
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.|Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China.
authors.forename: Anxin
authors.initials: A
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Zhongyao
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.|Global Health and Genomics, School of Medical and Health Sciences, Edith Cowan University, Perth, 6027, Australia.
authors.forename: Xinwei
authors.initials: X
authors.lastname: Yu
authors.affiliation: School of Public Health, Ningxia Medical University, Yinchuan, 750021, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Alzain
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Honghong
authors.initials: H
authors.lastname: Fang
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Manshu
authors.initials: M
authors.lastname: Song
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China. Yongzhou78214@163.com.|Department of Neurology, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100027, China. Yongzhou78214@163.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, 100069, China. wei.wang@ecu.edu.au.|Global Health and Genomics, School of Medical and Health Sciences, Edith Cowan University, Perth, 6027, Australia. wei.wang@ecu.edu.au.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000328:Adult; D002681:China; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003710:Demography; D005260:Female; D006293:Health Promotion; D006304:Health Status; D006801:Humans; D008297:Male; D011634:Public Health; D012107:Research Design
keywords: Cardiovascular events; Cerebrovascular events; Cohort study; Non-communicable chronic disease (NCD); Suboptimal health status (SHS)