Poor self-rated health is significantly associated with elevated C-reactive protein levels in women, but not in men, in the Japanese general population
Introduction
Self-rated health (SRH) is a measure based on a single question for individuals to rate their own health. There is widespread agreement that this global question provides a useful summary of how individuals perceive their overall health status [1]. SRH is a strong predictor of mortality even after adjusting for known demographic, social and medical risk factors [2]. A meta-analysis of community-based cohort studies has shown that persons with poor SRH had a 2-fold higher risk for all-cause mortality than that for persons with excellent SRH [3]. Poor SRH also contributes to increased risks for cardiovascular mortality and morbidity [4], [5], [6], [7]. However, the mechanisms for these associations are poorly understood, and there is a little information about the biological background of SRH [8].
Several studies have shown that poor SRH is significantly associated with low-grade inflammation expressed as mildly elevated levels of inflammatory markers [9], [10], [11], [12], [13], [14], [15]. Low-grade inflammation is associated with the development of many diseases such as cardiovascular disease, cancer and diabetes [16], [17], [18]. Therefore, findings in earlier studies suggest that low-grade inflammation could play an important role in the mechanism for the association between poor SRH and increased risks for mortality and morbidity.
Although studies conducted in general populations have shown a significant association between SRH and low-grade inflammation after adjusting for self-reported data, adjustment was not made in those studies for objectively measured clinical indicators, which are associated with both SRH [11], [19], [20], [21], [22] and low-grade inflammation [23], [24], [25], [26]. Therefore, sufficient adjustment for the association between SRH and low-grade inflammation might not have been made in those studies. In addition, a gender difference may exist in the association between SRH and low-grade inflammation [13]. However, most studies conducted in general populations could not reveal whether there is a gender difference in the association between SRH and low-grade inflammation because sex-stratified analysis was not performed in those studies.
The objective of this study was to clarify whether poor SRH is associated with low-grade inflammation, expressed as elevated C-reactive protein (CRP) levels, using data for a Japanese general population with adjustments for potential confounders including factors objectively measured separately by sex.
Section snippets
Study population
We analyzed baseline data of the Iwate-Kenpoku cohort (Iwate-KENCO) study, which was designed as a cohort study of community-dwelling residents living in the northern part of the main island of Japan. The methodology of the Iwate-KENCO study has been described elsewhere [27], [28]. The baseline survey was carried out between 2002 and 2005. A total of 17,706 participants (5614 men and 12,092 women) aged 40 to 69 years gave written informed consent for participation in this study. Of those
Results
Table 1 shows characteristics of male participants in the SRH groups. Compared to men with good SRH, men with poorer SRH had significantly lower HDLC levels, higher HbA1c levels, and higher prevalence of stroke and/or myocardial infarction. In men with poorer SRH, there were a higher proportion of past drinkers and lower proportions of persons who exercise ≥ 2 h per week, persons who sleep 7 to 8 h per day, persons who have a job and persons who are married. There was no significant linear trend
Discussion
In this large community-based study of apparently healthy Japanese people aged 40–69 years, the proportion of persons with elevated CRP (1.0 mg/L or higher) in the poor SRH group was significantly higher than that in the good SRH group for both men and women. This significant association remained after adjustment for socioeconomic status and health-related behaviors in women, while the significance disappeared after the adjustment in men. Furthermore, in women, a significant association between
Competing interest statement
The authors have no competing interests to report.
Acknowledgments
This study was supported by grants from the Japan Arteriosclerosis Prevention Fund, the Japanese Ministry of Health, Labour and Welfare (H17-Choju-025 and H19-Choju-030) and the Japanese Ministry of Education, Culture, Sports, Science and Technology (Grants-in-Aid for Scientific Research (C), No. 23590810). We would like to thank the staff of Iwate Health Service Association and the staff in all municipalities (Iwate Prefecture, Ninohe City, Ichinohe Town, Karumai Town, Kunohe Village, Yamada
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2019, SSM - Population HealthCitation Excerpt :Usually assessed with one question (e.g. “Overall, how would you rate your health?”), SRH is easy and cheap to collect and has been consistently linked to objective health measures (Christian et al., 2011; Jylhä, Volpato, & Guralnik, 2006; Leshem-Rubinow et al., 2015; Shanahan, Bauldry, Freeman, & Bondy, 2014; Tanno et al., 2012) and mortality (Idler & Benyamini, 1997; Lima-Costa, Cesar, Chor, & Proietti, 2012a). However, research has shown that the way people interpret and respond to the SRH question varies by age (Shooshtari, Menec, & Tate, 2007), gender (Benyamini, Leventhal, & Leventhal, 2000; Jylhä, Guralnik, Ferrucci, Jokela, & Heikkinen, 1998), and socioeconomic position (SEP) (Dowd & Zajacova, 2010).
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2014, Evolution and Human BehaviorCitation Excerpt :C-reactive protein levels prospectively predict a number of adverse outcomes such as cardiovascular disease (Danesh et al., 2004) and diabetes (Pradhan, Manson, Rifai, Buring, & Ridker, 2001), as well as consequent mortality (Kuller, Tracy, Shaten, & Meilahn, 1996; Wang et al., 2006). They correlate with self-rated health in women (Tanno et al., 2012). C-reactive protein levels also tend to increase with age (Hutchinson et al., 2000), making them in effect a marker of age-related increase in morbidity and tissue damage.
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2014, Annals of EpidemiologyCitation Excerpt :Third, participants with somatic complaints may have had subclinical somatic diseases that increase the mortality risk. In a recent study, poor self-rated health was associated with low-grade inflammation [41], which in turn is associated with the development of diseases such as CVD and cancer [42]. Nevertheless, adjusting for several somatic variables and a history of CVD, as well as the exclusion of those with a history of cancer, reduced the likelihood of this bias in the present study.
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2014, Brain, Behavior, and ImmunityCitation Excerpt :Indeed, one study reported that among individuals with less than “very good” self-rated health, men were more likely to die from cancer and also heart disease than women (Benjamins et al., 2004)—and both of these conditions are also associated with elevated hs-CRP (e.g., Ko et al., 2012; Ridker, 2007; Shah et al., 2009). We should also note, however, that our sex-differentiated findings were inconsistent with some studies from middle and older adulthood that reported that SRH-inflammatory marker associations were present in females even after accounting for health-related adiposity (Janszky et al., 2005; Unden et al., 2007), or that these association were stronger in females than in males (Lekander et al., 2004; Tanno et al., 2012). Jylhä (2009) proposed that sex differences in associations between SRH and its correlates and outcomes could change with age.