Relationship between high-sensitivity C-reactive protein, regular exercise, and handgrip strength in Korean older adults: a nationwide cross-sectional study
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Dynapenia increases the risk of frailty, disability, and mortality in older adults. Chronic inflammation and physical inactivity are considered major contributors. This study examined the associations of high-sensitivity C-reactive protein (hs-CRP) levels and regular exercise with dynapenia in older Korean adults.
Methods
We analyzed data from 4,935 adults aged ≥65 years who participated in the 2015–2018 Korea National Health and Nutrition Examination Survey. Dynapenia was defined as handgrip strength <28 kg in men and <18 kg in women. Serum hs-CRP levels were categorized as <1, 1–3, and >3 mg/L. Multivariable logistic regression was used to evaluate the associations of hs-CRP levels and exercise with dynapenia.
Results
The prevalence of dynapenia was 27.4%. Participants with dynapenia had higher adjusted mean hs-CRP levels than those without (1.60 mg/L vs. 1.25 mg/L, P=0.008). Compared with hs-CRP <1 mg/L, hs-CRP >3 mg/L was independently associated with dynapenia (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.26–2.10). Lack of resistance exercise (OR, 1.99; 95% CI, 1.52–2.61) and aerobic exercise (OR, 1.45; 95% CI, 1.20–1.75) were also independently associated with dynapenia. Participants with both hs-CRP >3 mg/L and no regular exercise had higher odds of dynapenia (OR, 2.69; 95% CI, 1.89–3.83) compared with those with hs-CRP <1 mg/L who exercised regularly.
Conclusion
Elevated hs-CRP levels and lack of regular exercise were independently associated with dynapenia, suggesting that reducing systemic inflammation and promoting regular exercise may help preserve muscle strength in older adults.
South Korea has the fastest aging rate among Organisation for Economic Co-operation and Development nations [1]. South Korea became an aged society in 2017 and a super-aged society in 2024. By the end of 2024, the older population (aged ≥65 years) will account for 20% of the total population [2].
Sarcopenia is characterized by decreased skeletal muscle mass, muscle strength, and physical performance due to aging [3]. It is associated with poor health outcomes including frailty, falls, fractures, and higher mortality rates in older adults [4,5]. Dynapenia (age-related loss of muscle strength) better predicts disability and mortality than muscle mass; among the methods for measuring muscle strength, handgrip strength is a noninvasive, reproducible, and easily obtained measure of muscular fitness [6]. It can be a valuable tool for screening health status, including the functional, psychological, and social health of older patients in primary care settings [7,8].
Although the pathogenesis of sarcopenia has not been fully elucidated, sarcopenia is associated with a lack of physical activity, malnutrition, and chronic inflammation [9,10]. Chronic low-grade inflammation resulting from age-related immune dysfunction leads to skeletal muscle wasting, muscle weakness, and worsening of physical performance. C-reactive protein (CRP) is an acute-phase protein produced in response to acute trauma or chronic diseases; it reflects the systemic inflammatory response and is related to age-related degenerative changes [11]. A systematic review and meta-analysis showed that both CRP and high-sensitivity CRP (hs-CRP) levels were significantly and negatively correlated with muscle strength [12]. In contrast, regular physical activity stimulates muscle growth, enhances endurance, and improves overall muscle function [13,14]. Also, there is some evidence that exercise interventions, including aerobic and resistance exercises, improved circulating inflammatory biomarkers in older adults [13,14].
In this context, we propose that there might be different associations between hs-CRP levels and muscle strength depending on whether older adults engage in regular exercise. By considering both aerobic and resistance exercises, our study offers a novel perspective on how exercise patterns are associated with inflammation-associated decline in muscle strength. Therefore, we investigated the association of hs-CRP levels (<1, 1–3, and >3 mg/L), type of exercise (aerobic and resistance exercises), and dynapenia using large representative data from the Korea National Health and Nutrition Examination Survey (KNHANES).
Methods
Study participants
This study used data from the KNHANES 2015–2018 which, a nationally representative survey conducted by the Korea Disease Control and Prevention Agency (KDCA). Of 31,649 KNHANES participants from 2015 to 2018 who completed the health interview and health examination surveys, we included 6,504 older adults (aged ≥65 years), and sequentially excluded participants who did not measure handgrip strength (n=683), did not measure hs-CRP level (n=410), and had missing data for dietary intake (n=476). Finally, 4,935 participants were included in the study.
The KNHANES was approved by the KDCA Institutional Review Board (No. 2018-01-03-P-A). KNHANES data are publicly available (https://knhanes.kdca.go.kr/knhanes/main.do). All procedures were performed in accordance with the Declaration of Helsinki, and signed informed consent was obtained from all participants.
Handgrip strength measurement
The handgrip strength was measured using a digital grip strength dynamometer (T.K.K. 5401; Takei Scientific Instruments Co. Ltd.). Trained examiners measured handgrip strength in a standing position with the forearm at thigh level and away from the body. The handgrip strength was measured in both hands alternately 3 times, for a total of six measurements, with 30 seconds of rest between each measurement. The maximum value was used as the final handgrip strength. Relative handgrip strength was calculated as handgrip strength divided by body mass index (BMI). Following the recommendations of the Asian Working Group for Sarcopenia 2019, we defined low grip strength (dynapenia) as handgrip strength less than 28 kg for men and less than 18 kg for women [3].
Measurement of hs-CRP
Serum hs-CRP levels were measured using a COBAS analyzer (Roche Diagnostics) and an immunoturbidimetric assay (Roche Cardiac C-reactive protein high-sensitive reagent kit). The analytical measurement range for hs-CRP concentrations was 0.15 to 20 mg/L. According to the American Heart Association and Centers for Disease Control and Prevention recommendations, hs-CRP levels were classified into three risk categories: low (<1 mg/L), intermediate (1–3 mg/L), and high (>3.0 mg/L) [15].
Assessment of other variables
Data were collected at a specially equipped mobile examination center. Participants were divided into three groups: 65 to 69 years, 70 to 79 years, and 80 years or older. Educational level was classified into elementary school, middle school, high school, and college or higher. Monthly household income was divided into the following quartiles: low, middle, upper middle, and high. Smoking status was classified as current (the participant had smoked more than 100 cigarettes in their lifetime and currently smoked), former (the participant had smoked more than 100 cigarettes in their lifetime and did not currently smoke), or never smoked (the participant had smoked less than 100 cigarettes in their lifetime and did not currently smoke). Alcohol consumption was defined as alcohol consumption of at least once per month. Physical activity was assessed using the Global Physical Activity Questionnaire, which consists of three domains: occupation, leisure, and transport [16]. Regular aerobic physical activity was defined as moderate-intensity physical activity 150 min/wk or more or vigorous-intensity physical activity 75 min/wk or more. Regular muscle strengthening exercise was defined as engaging in strength training, including sit-ups, push-ups, pull-ups using bars, and lifting dumbbells or barbells (≥2 times/wk). BMI was calculated by dividing weight by height squared (kg/m2). According to the guidelines of the World Health Organization of the Asia-Pacific Centre, we categorized BMI into three groups: underweight (<18.5 kg/m2), normal or overweight (18.5–24.9 kg/m2), and obese (≥25 kg/m2) [17]. Comorbidities were defined using questionnaires regarding doctor-diagnosed chronic diseases such as hypertension, diabetes, dyslipidemia, ischemic heart disease, cerebrovascular disease, chronic kidney disease, liver cirrhosis, osteoarthritis, rheumatoid arthritis, asthma, chronic obstructive pulmonary disease, thyroid diseases, depression, and malignancy.
Statistical analysis
The KNHANES used a complex sampling design, and we used a complex sample analysis to calculate the weighted mean and standard error (SE) for continuous data, and the proportion (%) and SE for categorical data. Student t-test was used to compare continuous data and the chi-square test was used to compare categorical variables. We compared the adjusted means of hs-CRP levels between the normal and dynapenia groups using analysis of covariance (ANCOVA). To estimate the association between hs-CRP levels, regular exercise, and dynapenia, we used a multivariable logistic regression analysis. Age and sex were adjusted for in Model 1, and BMI, household income, education, alcohol consumption, smoking status, total energy intake, protein intake, and comorbidity were additionally adjusted for in the final model. To evaluate the additive interaction between hs-CRP levels and regular exercise on dynapenia, we calculated the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and the Synergy Index (SI) using the delta method based on a fully adjusted logistic regression model (Model 2). RERI >0, AP >0, or SI >1 indicate a positive interaction on the additive scale. The 95% confidence intervals (CIs) of these measurements were estimated using the delta method. Statistical analyses were performed using IBM SPSS ver. 25.0 (IBM Corp.), and additive interaction measures were calculated using R ver. 4.5.2 (R Foundation for Statistical Computing). Statistical significance was set at P<0.05.
Results
Characteristics
Table 1 shows a comparison of characteristics of participants with and without dynapenia. A total of 4,935 participants were categorized into the normal group (n=3,582) and the dynapenia group (n=1,353) based on handgrip strength criteria. The prevalence of dynapenia was 27.4% in this study. Significant differences were observed between the two groups across a wide range of demographic variables. Participants with dynapenia were older than those without dynapenia (P<0.001). The dynapenia group had a higher proportion of female and underweight individuals (BMI <18.5 kg/m2)
The dynapenia group had a higher proportion of individuals with lower educational attainment and household income (all P<0.001). In the dynapenia group, 71.5% did not complete elementary school, compared to 49.7% in the normal group. Similarly, 57.8% of those with dynapenia were in the lowest income quartile compared with 38.8% in the normal group.
Lifestyle behaviors also differed between the groups. The dynapenia group had a higher percentage of never smokers (68.6% vs. 58.2%, P<0.001), while the percentage of current smokers was lower (7.9% vs. 9.5%, P<0.001). Alcohol drinking (defined as drinking more than once per month) was also less frequent in the dynapenia group (27.0% vs. 40.7%, P<0.001).
However, the dynapenia group engaged less in both resistance and aerobic exercises (all P<0.001). Only 9.2% of the dynapenia group engaged in resistance exercise (≥2 times/wk), compared with 24.4% in the normal group. Similarly, the proportions of individuals performing aerobic exercise were 22.1% in the dynapenia group and 37.4% in the normal group. Consistently, the proportion of participants who engaged in regular exercise, defined as meeting the criteria for aerobic or resistance exercise, was significantly lower in the dynapenia group than in the normal group (27.7% vs. 49.8%, P<0.001).
Handgrip strength and relative handgrip strength were significantly lower in the dynapenia group (17.82 kg vs. 29.40 kg, and 0.77 vs. 1.23, respectively; P<0.001). The distribution of hs-CRP levels showed that a higher proportion of dynapenic individuals had CRP levels 3 mg/L or greater (14.6% vs. 9.4%, P<0.001). Both energy and protein intake were lower in the dynapenia group than in those without dynapenia (all P<0.001). The mean daily energy intake was 1,499.7 kcal in the dynapenia group and 1,773.1 kcal in the normal group. Protein intake followed a similar trend (47.38 g vs. 59.23 g).
In addition, we compared the baseline characteristics of participants with complete dietary intake data and those with missing dietary data (Supplement 1). Most demographic and clinical variables were comparable between the two groups. However, significant differences were observed in age distribution, smoking status, and absolute handgrip strength. These findings suggest that, although the overall characteristics were largely similar, the possibility of residual selection bias related to the exclusion of participants with missing dietary data cannot be completely ruled out.
Crude and adjusted means of hs-CRP levels in patients with dynapenia
Table 2 shows the mean hs-CRP levels of individuals with and without dynapenia. All models showed that hs-CRP levels were significantly higher in the dynapenia group than in the normal group.
In the crude model, mean hs-CRP was 1.72 mg/L in the dynapenia group, significantly higher than the 1.36 mg/L in the normal group (P<0.001). After adjusting for age and sex (Model 1), the difference remained statistically significant (P=0.002), with hs-CRP values of 1.72 mg/L in the dynapenia group and 1.37 mg/L in the normal group. Even after adjustment for age, sex, BMI, income, education, alcohol drinking, smoking status, exercise, dietary intake, and comorbidities (Model 2), the mean hs-CRP level remained higher in the dynapenia group (1.60 mg/L; 95% CI, 1.38–1.82 mg/L) than in the normal group (1.25 mg/L; 95% CI, 1.11–1.40 mg/L), with statistical significance (P=0.008).
Multivariable analysis of hs-CRP, regular exercise, and dynapenia
Table 3 presents the results of multivariate analyses assessing the association of hs-CRP levels, regular exercise, resistance exercise, and aerobic exercise with dynapenia. After adjusting for age, sex, BMI, socioeconomic and lifestyle factors, and comorbidities (Model 2), individuals who did not engage in regular exercise had significantly higher odds of dynapenia than those who did (odds ratio [OR], 1.67; 95% CI, 1.39–2.00). Participants with high hs-CRP levels (>3 mg/L) showed significantly increased odds of dynapenia compared to those with low hs-CRP levels (<1 mg/L) (OR, 1.63; 95% CI, 1.26–2.10). In terms of specific types of physical activity, resistance exercise less than twice per week (OR, 1.99; 95% CI, 1.52–2.61) and a lack of aerobic exercise (OR, 1.45; 95% CI, 1.20–1.75) were both independently associated with higher odds of dynapenia.
The prevalence of dynapenia according to hs-CRP and regular exercise
Figure 1 presents the prevalence of dynapenia stratified by combined hs-CRP level and regular exercise status. The prevalence of dynapenia was the lowest among participants with low hs-CRP levels who engaged in regular exercise (14.8%). In contrast, participants with high hs-CRP levels who did not exercise regularly had the highest prevalence of dynapenia (43.3%). Within each hs-CRP category, absence of regular exercise was consistently associated with a higher prevalence of dynapenia. In the low hs-CRP group, those who did not exercise regularly had a prevalence of 31.3%, compared with 14.8% in those who exercised regularly. Similarly, in the intermediate hs-CRP group (1–3 mg/L), the prevalence increased from 17.3% with exercise to 33.8% without exercise (P for trend <0.001).
Association between hs-CRP level, regular exercise, and dynapenia
Using the group with a low hs-CRP level and regular exercise as the reference group, participants with intermediate hs-CRP levels who regularly exercised did not have significantly increased odds of dynapenia (OR, 1.13; 95% CI, 0.80–1.58). However, those with a high hs-CRP level who regularly exercised had a higher odds of dynapenia (OR, 1.65; 95% CI, 1.05–2.58), despite maintaining exercise (Table 4). Those with low hs-CRP levels who lacked regular exercise exhibited higher odds of developing dynapenia (OR, 1.66; 95% CI, 1.31–2.10). The odds of dynapenia were further increased among those with an intermediate hs-CRP level and no regular exercise (OR, 1.92; 95% CI, 1.46–2.52). The highest odds of dynapenia were observed in the group with high hs-CRP levels and no regular exercise (OR, 2.69; 95% CI, 1.89–3.83), even after adjustment for confounding factors (Model 2). In the fully adjusted model, the RERI for hs-CRP levels of 1 to 3 mg/L combined without regular exercise was 0.14 (95% CI, −0.43 to 0.71), and for hs-CRP levels greater than 3 mg/L combined without regular exercise was 0.39 (95% CI, −0.69 to 1.47).
The AP and SI were also not statistically significant with CIs of 0 and 1, respectively. These findings indicated no significant additive interaction between hs-CRP levels and regular exercise (Supplement 2).
Discussion
This study elucidated the relationship between chronic low-grade inflammation (inflammaging), exercise, and muscle strength decline in the older Korean population (aged ≥65 years). Higher hs-CRP levels (>3 mg/L) or lack of regular exercise were significantly associated with higher odds of dynapenia. Compared with the low hs-CRP level and regular exercise groups, the low, intermediate, and high hs-CRP level groups lacking regular exercise exhibited higher odds of dynapenia (OR, 1.66; 95% CI, 1.31–2.10; OR, 1.92; 95% CI, 1.46–2.52; and OR, 2.69; 95% CI, 1.89–3.83; respectively). However, participants with intermediate hs-CRP levels and regular exercise did not have significantly higher odds of dynapenia (OR, 1.13; 95% CI, 0.80–1.58), and participants with high hs-CRP levels and regular exercise had slightly higher odds of dynapenia (OR, 1.65; 95% CI, 1.05–2.58).
Inflammaging, a chronic low-grade inflammatory state resulting from age-related immune dysfunction, is a major contributor to sarcopenia [18,19]. Elevated circulating pro-inflammatory cytokine levels (interleukin [IL]-6, tumor necrosis factor [TNF]-α, CRP) disrupt muscle protein balance, leading to atrophy. Factors such as increased visceral fat inflammation, gut permeability, and immunosenescence exacerbate inflammation. hs-CRP, an indicator of low-grade inflammation, is elevated in sarcopenia and sarcopenic obesity and correlates with muscle protein catabolism. Inflammatory cytokines profoundly affect key intracellular signaling pathways that regulate muscle protein metabolism. These cytokines impair muscle protein synthesis by affecting key intracellular signaling pathways, notably the Akt/mTOR pathway, while simultaneously promoting protein degradation via systems such as the ubiquitin-proteasome pathway [19].
In this study, the observed inverse correlation between elevated hs-CRP levels and lower handgrip strength aligns with previous research on the detrimental effects of inflammation on muscle health. A meta-analysis by Tuttle et al. [20] found that higher levels of inflammatory markers were linked to lower muscle strength and mass. Studies on Korean older adults by Son et al. [21] and Choi and Shin [22] consistently found a significant inverse association between hs-CRP level and handgrip strength, as an indicator for possible sarcopenia. Nevertheless, it should be noted that transient factors, such as acute infections or inflammatory episodes, might have contributed to temporary fluctuations in hs-CRP levels, which could not be completely excluded from our analysis.
In this large population-based study, elevated hs-CRP levels and lack of regular exercise were independently associated with increased odds of developing dynapenia after adjusting for demographic, socioeconomic, lifestyle, nutritional, and clinical factors. Participants exposed to both elevated systemic inflammation and physical inactivity exhibited the highest odds of developing dynapenia, indicating that the coexistence of these two conditions may contribute to a greater burden on muscle strength. However, additional analyses evaluating the additive interaction between hs-CRP levels and regular exercise did not demonstrate statistically a significant interaction based on the RERI, AP, and SI measures. Although the point estimates were positive, the CIs include null values. Because interaction analyses, particularly on an additive scale, generally require larger sample sizes than main-effect analyses, the possibility of modest interactions cannot be completely excluded.
Regular physical activity has been associated with improved muscle strength and physical function in older adults. Khalafi et al. [23] demonstrated that combined exercise training (aerobic and resistance exercises) effectively reduced inflammatory markers such as IL-6 and CRP in older adults. Sanchez-Sanchez et al. [24] reported that moderate to vigorous physical activity was associated with a lower risk of sarcopenia in older individuals. Several physiological mechanisms may explain the beneficial effects of exercise in maintaining muscle health. Physical activity can reduce body fat, particularly visceral adiposity, which is associated with lower levels of systemic pro-inflammatory cytokines. In addition, exercise training has been reported to improve mitochondrial function and protein quality control, which may contribute to the preservation of muscle function during aging.
Handgrip strength is a prognostic indicator of all-cause mortality in older adults. Smith et al. [25] suggested that inflammatory markers partially explain this link. Our findings showed that regular resistance and aerobic exercises were associated with lower odds of dynapenia across hs-CRP strata. These results support the potential role of exercise as an important nonpharmacological strategy for maintaining muscle strength in older adults. In primary care clinics, handgrip strength measurement, which is simple, low-cost, and noninvasive, can be incorporated into routine primary care visits as a screening tool for functional decline [26]. Physicians can incorporate structured resistance training prescriptions, performed at least twice weekly, involving the upper and lower body muscle groups, with one to three sets of six to 12 repetitions performed at a relatively high level of effort [27]. Regular reassessment of grip strength enables monitoring of treatment response and adjustment of exercise intensity. Moreover, community-based programs offering regular aerobic and resistance exercise sessions, such as those organized in public health centers or senior community centers, could serve as accessible interventions to reduce systemic inflammation and maintain muscle strength in older adults [24]. Integrating such exercise initiatives with national health insurance policies may not only improve individual health outcomes, but also contribute to reducing healthcare expenditures associated with falls, disability, and chronic disease management in aging populations.
The strengths of this study include the use of a large-scale, nationally representative data (KNHANES 2015–2018), focusing on Korean adults aged 65 years or older, enhancing generalizability. Objective handgrip strength measurements were performed and analysis was adjusted for major confounding variables. The exploration of exercise-type interactions further highlights the potential for tailored interventions. The findings of this study have significant clinical implications for promoting health and preventing sarcopenia in the older population. hs-CRP, being an inexpensive and available biomarker in clinical practice, could be repurposed to serve as a valuable and simple tool for predicting low handgrip strength in older adults at risk, aiding in the early identification of individuals susceptible to sarcopenia and enabling timely preventive interventions to slow disease progression and improve outcomes. This involves leveraging handgrip strength as an easily measured quantitative tool for physicians to regularly monitor sarcopenia [26].
Despite its strengths, our study has several limitations. First, the cross-sectional design prevented the establishment of causality between the hs-CRP levels and muscle decline. Second, the analysis relied solely on hs-CRP, limiting consideration of other inflammatory markers (IL-6, TNF-α), and we lacked data on other components of sarcopenia (muscle mass and physical function). Third, potential unmeasured confounders cannot be entirely ruled out. While we adjusted for comorbidities, including rheumatoid arthritis, specific conditions known to elevate systemic inflammation (e.g., specific nonrheumatoid autoimmune diseases) may persist. Crucially, the KNHANES dataset did not include the use of anti-inflammatory medications such as nonsteroidal anti-inflammatory drugs or corticosteroids, which could artificially suppress hs-CRP levels and influence the observed associations. Fourth, participants with missing dietary intake data were excluded from the analysis. Although most baseline characteristics were comparable, a residual selection bias could not be entirely excluded. Finally, the reliance on self-reported physical activity data may have introduced recall bias. Specifically, self-reported physical activity in older adults tends to be inaccurate due to memory limitations and perception of actual physical activity levels, and detailed information on the intensity and duration of the exercise was unavailable, potentially obscuring a more precise dose-response relationship. Future studies should aim to demonstrate the effects of exercise interventions on reducing various inflammatory markers and improving the components of sarcopenia (muscle mass, strength, and physical function) in older adults while simultaneously using objective measurement tools for physical activity and accounting for medication use that influences systemic inflammation.
In conclusion, this study demonstrated that elevated hs-CRP levels and a lack of regular exercise were independently associated with dynapenia, and individuals exposed to both risk factors exhibited the greatest vulnerability. These findings highlight the need for integrated strategies to reduce systemic inflammation and encourage exercise to preserve muscle strength in older adults.
Notes
Conflict of interest
No potential conflict of interest relevant to this article was reported.
Funding
None.
Data availability
Publicly available datasets were analyzed in this study. These data can be found at https://knhanes.kdca.go.kr (Korea National Health and Nutrition Examination Survey, 2015–2018).
Author contribution
Conceptualization: SSP. Data curation: YK, HMN. Formal analysis: YK, HMN. Investigation: HJS, KHP. Methodology: SSP, YGS. Validation: YJP, HJA. Supervision: HMN. Writing–original draft: SSP. Writing–review & editing: HJS, KHP, YGS, YJP, HJA, HMN. Final approval of the manuscript: all authors.
The prevalence of dynapenia according to high-sensitivity Creactive protein (hs-CRP) level and regular exercise. P for trend <0.001 by linear regression analysis. EX, regular exercise.
Table 1.
General characteristics of the participants
Characteristic
Normal (n=3,582)
Dynapenia (n=1,353)
P-value
Age (y)
<0.001
65–69
40.5 (1.0)
14.5 (1.0)
70–79
50.9 (1.0)
51.6 (1.5)
≥80
8.6 (0.6)
33.8 (1.5)
Male sex
50.3 (0.9)
36.2 (1.5)
<0.001
Body mass index (kg/m2)
<0.001
<18.5
1.4 (0.2)
4.9 (0.7)
18.5–24.9
59.7 (1.0)
62.2 (1.6)
≥25.0
38.9 (1.0)
32.9 (1.5)
Education attainment
<0.001
Less than elementary school
49.7 (1.2)
71.5 (1.7)
Middle school
16.2 (0.8)
10.8 (1.1)
High school
20.9 (0.9)
10.8 (1.2)
College and higher
13.2 (0.8)
6.9 (1.0)
Household income
<0.001
Low
38.8 (1.2)
57.8 (1.9)
Lower middle
28.9 (1.0)
21.5 (1.4)
Upper middle
18.7 (0.9)
12.8 (1.3)
High
13.5 (1.0)
7.9 (1.0)
Smoking
<0.001
Never smoker
58.2 (0.9)
68.6 (1.5)
Ex-smoker
32.3 (0.9)
23.6 (1.4)
Current smoker
9.5 (0.6)
7.9 (1.0)
Alcohol drinking
40.7 (1.0)
27.0 (1.4)
<0.001
Resistance exercise (≥2 times/wk)
24.4 (0.9)
9.2 (1.0)
<0.001
Aerobic exercise
37.4 (1.1)
22.1 (1.4)
<0.001
Regular exercise
49.8 (1.1)
27.7 (1.5)
<0.001
Handgrip strength (kg)
29.40 (0.15)
17.82 (0.17)
<0.001
Relative handgrip strength (kg/BMI)
1.23 (0.01)
0.77 (0.01)
<0.001
hs-CRP (mg/L)
<0.001
<1
67.8 (0.9)
62.0 (1.5)
1–3
22.8 (0.8)
23.4 (1.3)
>3
9.4 (0.5)
14.6 (1.1)
Multimorbidity
0.619
≥3
21.9 (0.8)
23.4 (1.4)
1–2
57.5 (1.0)
56.5 (1.6)
0
20.6 (0.8)
20.1 (1.2)
Total energy intake (kcal/d)
1,773.1 (17.0)
1,499.7 (21.6)
<0.001
Protein intake (g/d)
59.23 (0.66)
47.38 (0.87)
<0.001
Values are presented as the weighted percentage (standard error) or estimated mean (standard error). P-values are derived from the Student t-test for continuous variables and the chi-square test for categorical variables.
hs-CRP, high-sensitivity C-reactive protein.
Table 2.
The crude and adjusted means of hs-CRP level and dynapenia
Values are presented as mean (95% confidence interval). Adjusted means of hs-CRP between the normal and dynapenia group were compared using analysis of covariance.
hs-CRP, high-sensitivity C-reactive protein.
a)Model 1: adjusted for age and sex.
b)Model 2: adjusted for age, sex, body mass index, household income, education, alcohol drinking, smoking status, resistance exercise, aerobic exercise, total energy intake, protein intake, and comorbidity.
Table 3.
Multivariable analysis of hs-CRP level, regular exercise, and dynapenia
Values are presented as odds ratio (95% confidence interval). Multivariable logistic regression analysis. Regular exercise was defined as participation in resistance exercise or aerobic exercise.
hs-CRP, high-sensitivity C-reactive protein.
a)Model 1: adjusted for age and sex.
b)Model 2: adjusted for age, sex, body mass index, household income, education, alcohol drinking, smoking status, total energy intake, protein intake, and comorbidity.
c)When hs-CRP was analyzed as the exposure variable, resistance and aerobic exercise were included as covariates.
d)When regular exercise was analyzed as the exposure variable, hs-CRP was included as a covariate.
e)When resistance exercise was analyzed as the exposure variable, hs-CRP and aerobic exercise were included as covariates.
f)When aerobic exercise was analyzed as the exposure variable, hs-CRP and resistance exercise were included as covariates.
Table 4.
Association between hs-CRP level, regular exercise, and dynapenia
Values are presented as odds ratio (95% confidence interval). Multivariable logistic regression analysis. Regular exercise was defined as participation in resistance exercise or aerobic exercise.
hs-CRP, high-sensitivity C-reactive protein.
a)Model 1: adjusted for age and sex.
b)Model 2: adjusted for age, sex, body mass index, household income, education, alcohol drinking, smoking status, total energy intake, protein intake, and comorbidity.
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Relationship between high-sensitivity C-reactive protein, regular exercise, and handgrip strength in Korean older adults: a nationwide cross-sectional study
Figure. 1. The prevalence of dynapenia according to high-sensitivity Creactive protein (hs-CRP) level and regular exercise. P for trend <0.001 by linear regression analysis. EX, regular exercise.
Graphical abstract
Figure. 1.
Graphical abstract
Relationship between high-sensitivity C-reactive protein, regular exercise, and handgrip strength in Korean older adults: a nationwide cross-sectional study
Characteristic
Normal (n=3,582)
Dynapenia (n=1,353)
P-value
Age (y)
<0.001
65–69
40.5 (1.0)
14.5 (1.0)
70–79
50.9 (1.0)
51.6 (1.5)
≥80
8.6 (0.6)
33.8 (1.5)
Male sex
50.3 (0.9)
36.2 (1.5)
<0.001
Body mass index (kg/m2)
<0.001
<18.5
1.4 (0.2)
4.9 (0.7)
18.5–24.9
59.7 (1.0)
62.2 (1.6)
≥25.0
38.9 (1.0)
32.9 (1.5)
Education attainment
<0.001
Less than elementary school
49.7 (1.2)
71.5 (1.7)
Middle school
16.2 (0.8)
10.8 (1.1)
High school
20.9 (0.9)
10.8 (1.2)
College and higher
13.2 (0.8)
6.9 (1.0)
Household income
<0.001
Low
38.8 (1.2)
57.8 (1.9)
Lower middle
28.9 (1.0)
21.5 (1.4)
Upper middle
18.7 (0.9)
12.8 (1.3)
High
13.5 (1.0)
7.9 (1.0)
Smoking
<0.001
Never smoker
58.2 (0.9)
68.6 (1.5)
Ex-smoker
32.3 (0.9)
23.6 (1.4)
Current smoker
9.5 (0.6)
7.9 (1.0)
Alcohol drinking
40.7 (1.0)
27.0 (1.4)
<0.001
Resistance exercise (≥2 times/wk)
24.4 (0.9)
9.2 (1.0)
<0.001
Aerobic exercise
37.4 (1.1)
22.1 (1.4)
<0.001
Regular exercise
49.8 (1.1)
27.7 (1.5)
<0.001
Handgrip strength (kg)
29.40 (0.15)
17.82 (0.17)
<0.001
Relative handgrip strength (kg/BMI)
1.23 (0.01)
0.77 (0.01)
<0.001
hs-CRP (mg/L)
<0.001
<1
67.8 (0.9)
62.0 (1.5)
1–3
22.8 (0.8)
23.4 (1.3)
>3
9.4 (0.5)
14.6 (1.1)
Multimorbidity
0.619
≥3
21.9 (0.8)
23.4 (1.4)
1–2
57.5 (1.0)
56.5 (1.6)
0
20.6 (0.8)
20.1 (1.2)
Total energy intake (kcal/d)
1,773.1 (17.0)
1,499.7 (21.6)
<0.001
Protein intake (g/d)
59.23 (0.66)
47.38 (0.87)
<0.001
hs-CRP
Normal
Dynapenia
P-value
Crude
1.36 (1.27–1.44)
1.72 (1.54–1.89)
<0.001
Model 1a)
1.37 (1.28–1.46)
1.72 (1.53–1.91)
0.002
Model 2b)
1.25 (1.11–1.40)
1.60 (1.38–1.82)
0.008
Variable
Crude
Model 1a)
Model 2b)
hs-CRP (mg/L)
<1
1
1
1
1–3
1.12 (0.95–1.33)
1.06 (0.89–1.27)
1.15 (0.95–1.39)
>3
1.70 (1.37–2.09)
1.68 (1.33–2.13)
1.63 (1.26–2.10)
Regular exercise
(+)c)
1
1
1
(–)d)
2.59 (2.20–3.06)
1.86 (1.56–2.21)
1.67 (1.39–2.00)
Resistance exercisee)
≥2 times/wk
1
1
1
<2 times/wk
3.18 (2.49–4.06)
2.28 (1.76–2.96)
1.99 (1.52–2.61)
Aerobic exercisef)
(+)
1
1
1
(–)
2.10 (1.76–2.50)
1.58 (1.32–1.89)
1.45 (1.20–1.75)
Variable
Crude
Model 1a)
Model 2b)
hs-CRP <1 and regular exercise (+)
1
1
1
hs-CRP 1–3 and regular exercise (+)
1.21 (0.88–1.68)
1.10 (0.79–1.51)
1.13 (0.80–1.58)
hs-CRP >3 and regular exercise (+)
1.68 (1.12–2.54)
1.66 (1.09–2.53)
1.65 (1.05–2.58)
hs-CRP <1 and regular exercise (–)
2.63 (2.14–3.24)
1.85 (1.49–2.31)
1.66 (1.31–2.10)
hs-CRP 1–3 and regular exercise (–)
2.95 (2.31–3.76)
2.00 (1.54–2.58)
1.92 (1.46–2.52)
hs-CRP >3 and regular exercise (–)
4.23 (3.12–5.76)
3.00 (2.14–4.21)
2.69 (1.89–3.83)
Table 1. General characteristics of the participants
Values are presented as the weighted percentage (standard error) or estimated mean (standard error). P-values are derived from the Student t-test for continuous variables and the chi-square test for categorical variables.
hs-CRP, high-sensitivity C-reactive protein.
Table 2. The crude and adjusted means of hs-CRP level and dynapenia
Values are presented as mean (95% confidence interval). Adjusted means of hs-CRP between the normal and dynapenia group were compared using analysis of covariance.
hs-CRP, high-sensitivity C-reactive protein.
Model 1: adjusted for age and sex.
Model 2: adjusted for age, sex, body mass index, household income, education, alcohol drinking, smoking status, resistance exercise, aerobic exercise, total energy intake, protein intake, and comorbidity.
Table 3. Multivariable analysis of hs-CRP level, regular exercise, and dynapenia
Values are presented as odds ratio (95% confidence interval). Multivariable logistic regression analysis. Regular exercise was defined as participation in resistance exercise or aerobic exercise.
hs-CRP, high-sensitivity C-reactive protein.
Model 1: adjusted for age and sex.
Model 2: adjusted for age, sex, body mass index, household income, education, alcohol drinking, smoking status, total energy intake, protein intake, and comorbidity.
When hs-CRP was analyzed as the exposure variable, resistance and aerobic exercise were included as covariates.
When regular exercise was analyzed as the exposure variable, hs-CRP was included as a covariate.
When resistance exercise was analyzed as the exposure variable, hs-CRP and aerobic exercise were included as covariates.
When aerobic exercise was analyzed as the exposure variable, hs-CRP and resistance exercise were included as covariates.
Table 4. Association between hs-CRP level, regular exercise, and dynapenia
Values are presented as odds ratio (95% confidence interval). Multivariable logistic regression analysis. Regular exercise was defined as participation in resistance exercise or aerobic exercise.
hs-CRP, high-sensitivity C-reactive protein.
Model 1: adjusted for age and sex.
Model 2: adjusted for age, sex, body mass index, household income, education, alcohol drinking, smoking status, total energy intake, protein intake, and comorbidity.
, Yejin Kim2
