Background Suboptimal health status (SHS) is a reversible borderline condition between optimal health and diseases. Although the definition of SHS is widely understood, the questionnaires of SHS are needed to be further developed, by which individual with SHS can be identified from a variety of population in the context of predictive, preventive and personalized medicine (PPPM/3PM). This study aimed to develop a short form of suboptimal health status questionnaire (SHSQ-SF) by reference to suboptimal health status questionnaire-25 (SHSQ-25). Methods A total of 6,183 participants enrolled from southern China were included in a training set, while 4,113 from northern China were included in an external validation set. SHSQ-SF included nine key items from SHSQ-25, a questionnaire that has been applied in Caucasians, Asians, and Africans. Item analysis, reliability and validity tests were carried out to validate SHSQ-SF. Receiver operating characteristic (ROC) curve was used to identify the optimal cutoff value for diagnosis of SHS. Results In the training dataset, the Cronbach s α coefficient was 0.902, and the split-half reliability was 0.863. The Kaiser-Meyer-Olkin (KMO) statistic was 0.880, and the Bartlett s test of sphericity was significant (χ2 = 32,929.680, P<0.05). Both Kaiser s criteria (eigenvalues >1) and scree plot revealed one factor which explained 57.008% of the total variance. Standardized factor loadings of confirmatory factor analysis (CFA) indices were between 0.59 to 0.74, with χ2/df = 4.972, (GFI) = 0.996, CFI = 0.996, RFI = 0.989 and RMSEA = 0.031. The area under ROC curve (AUC) was 0.985 (95%CI: 0.983 - 0.988) in training dataset, by which the cutoff value (χ11) was identified for diagnosis of SHS. In the external validation dataset, this questionnaire showed good discriminatory power (AUC = 0.975, 95%CI: 0.971-0.979), with a sensitivity of 96.2% and specificity of 87.4%. Conclusions We developed a short form of SHS questionnaire, which has good reliability and validity in measurement of SHS in Chinese residents. From the perspective of PPPM/3PM, SHSQ-SF is recommended to be used for quickly screening individuals with SHS from a large-scale population. Keywords Predictive preventive and personalized medicine (PPPM/3PM); Suboptimal health status (SHS); Questionnaire; Reliability; Validity

The authors have declared no competing interest.

This work was supported by Natural Science Foundation of Shandong Province (ZR2022MH082) and Scientific Research Foundation of Education Department of Yunnan Province (2021J1359).

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The Ethics Committee of Shandong First Medical University (SDFMU) approved this study.

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