The effects of protective or risk factors on suboptimal health status evaluated by subjective or objective measures

Author Identifier



Date of Award


Document Type

Thesis - ECU Access Only

Degree Name

Doctor of Philosophy


School of Medical and Health Sciences

First Supervisor

Wei Wang

Second Supervisor

Tony Blazevich

Third Supervisor

Rachel Alexander



Suboptimal health status (SHS) is an intermediate and reversible stage between health and disease and has become a major public health concern worldwide. SHS is characterised by chronic fatigue, perception of health complaints, general weakness, and a cluster of lasting physical symptoms. Therefore, it is warranted to comprehensively investigate the potential protective or risk factors for SHS and the possible measures to evaluate SHS to inform the prevention for SHS and subsequent diseases.


Study I. To explore the effects of tourism-related characteristics on SHS in a cross-sectional study.

Study II. To determine whether 2-week severe physical activity restriction induces pro-inflammatory alterations in immunoglobulin G (IgG) N-glycosylation profiles.

Study III. To translate the Suboptimal Health Status Questionnaire-25 (SHSQ-25) from its English version into the Korean language and to evaluate the validity and reliability of the Korean version of SHSQ-25 (K-SHSQ-25) in a Korean population.


Study I. A cross-sectional study was conducted between October and December 2021 in Shandong Province, China. Individuals were recruited via convenience sampling; all potential respondents were approached at random. SHSQ-25 was used to identify the SHS of the participants. Modified Poisson regression was the primary method to evaluate associations between tourism-related characteristics on SHS.

Study II. A quasi-experimental study was conducted within the parental clinical trial, Nutrition and Exercise Training (NExT) Study, with a sample of 79 healthy female participants from 40 to 60 years old. The participants were directed to exert their maximum effort towards reducing their daily step count monitored and recorded by a pedometer. The IgG N-glycosylation profile, which is an objective marker for SHS, was compared before and after physical activity restriction.

Study III. This study was carried out to translate SHSQ-25 from English into Korean according to international guidelines set forth by the World Health Organization (WHO) for health instrument translation between different languages. A subsequent cross-sectional study was conducted to evaluate the validity and reliability of K-SHSQ-25 in a Korean sample.


In Study I, 360 participants were included in the final analysis. The prevalence of SHS in the participants was 36.4% (131/310), with 67.2% for females and 32.8% for males. Poisson regression analysis with SHS as the dependent variable indicated that tourism expenditure during one’s prior trip (1,001-5,000 RMB; P = 0.006) was a risk factor significantly associated with SHS. Conversely, preference for domestic travel (Group tour, P = 0.006) was a significantly protective factor for SHS.

In Study II, during the 2-week activity restriction period, the daily step count was reduced by 76.8% to 1830 ± 680 steps per day. After physical activity restriction, the abundances of monogalactosylated and digalactosylated IgG N-glycans were reduced by 0.41 (95% CI -0.95 to -0.20; P = 0.045) and 0.53 (95% CI -0.88 to -0.18; P = 0.041), respectively.

In Study III, the K-SHSQ-25 achieved linguistic, cultural, and conceptual equivalence to the English version. The intraclass correlation coefficient of test-retest reliability for individual items ranged from 0.88 to 0.99. Reliability estimated based on internal consistency reached a Cronbach’s α of 0.953. The confirmatory factor analysis revealed that the root-mean-square error of approximation (RMSEA), goodness-of-fit index (GFI) and adjusted goodness of fit index (AGFI) were excellent (RMSEA = 0.069 < 0.08, GFI = 0.929 > 0.90, AGFI = 0.907 > 0.90). Regarding convergent validity, the five domains of the K-SHSQ-25 showed significant correlations with each other (r: 0.59-0.81, P < 0.001).


Study I. Findings suggested that tourism activities may serve as ideal interventions for leveraging SHS. In addition, tourism may present a new avenue for contributing to global health studies.

Study II. Short periods of enforced activity restriction, including those resulting from COVID lock-down or isolation, can trigger pro-inflammatory changes in IgG N-glycosylation profiles.

Study III. Results indicated that the Korean version of SHSQ-25, K-SHSQ-25 is a transcultural equivalent, robust, valid, and reliable assessment tool for evaluating SHS in the Korean-speaking population.



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