Rationale and design of the cardiorespiratory fitness and hospitalization events in armed forces study in Eastern Taiwan

Association of Tobacco Smoking with Physical Fitness of Military Males in Taiwan: The CHIEF Study

Tobacco smoking has been found associated with lower cardiorespiratory fitness in white and black males; however, few studies have not been conducted to clarify such relationship in Asian males. We performed a cross-sectional study to investigate the association between tobacco smoking status and physical fitness in 3,669 military males, averaged 29.4 years of age, from the cardiorespiratory fitness and hospitalization events in armed forces (CHIEF) study in Taiwan during 2014. There were 1,376 current smokers, and the others were noncurrent smokers. The effective sample size estimated was 1,230 participants, as the margin of error was ±3% at the 99% confidence level. Physical fitness was evaluated by time for a 3000-meter run test (aerobic fitness) and repetitive numbers of 2-minute sit-ups and 2-minute push-ups (anaerobic fitness) where all procedures were standardized by using computerized scoring systems. A multiple linear analysis adjusting for age, service specialty, body mass index, heart rate, alcohol intake, and training frequency was used to determine the relationship. As compared with noncurrent smoking, current smoking was inversely correlated with longer time for a 3000-meter run (β = 15.66 (95% confidence intervals (CI): 10.62, 20.70)) and fewer repetitive numbers of 2-minute sit-ups and 2-minute push-ups (β = −1.53 (95% CI: −2.08, −0.97) and −1.31 (95% CI: −2.12, −0.50), respectively). Our finding reconfirms the concept that tobacco smoking might reduce both aerobic and anaerobic fitness among young Asian males.

Sex-Specific Association Between Serum Uric Acid and Elevated Alanine Aminotransferase in a Military Cohort: The CHIEF Study

AIM

The study was conducted in order to examine the sex-specific association of serum uric acid (SUA) levels with elevated serum alanine aminotransferase (ALT) in a Taiwanese military cohort.

METHODS

We made a cross-sectional examination of the sex-specific relationship using 6728 men and 766 women, aged 18-50 years from a large military cohort in Taiwan. SUA levels within the reference range (<7.0 mg/dL for men and <5.7 mg/dL for women respectively) were divided into quartiles and SUA levels greater than the upper reference limits were defined as hyperuricemia. Elevated ALT levels were defined as ≥40 U/L. Multivariate logistic regression analysis was performed to determine the association between each SUA category and elevated ALT levels in men and women, respectively.

RESULTS

The prevalence of hyperuricemia and elevated ALT in men were 18.7% and 12.7%, respectively, and in women were 3.3% and 2.1%, respectively. As compared with the lowest SUA quartile, hyperuricemia was associated with elevated ALT in men (odds ratios (OR): 1.62, 95% confidence intervals (CI): 1.19-2.20) after controlling for age, service specialty, body mass index, metabolic syndrome components, current cigarette smoking, alcohol intake status, and weekly exercise times, but the associations for the other SUA quartiles were null. By contrast, the associations of hyperuricemia (OR: 0.81, 95% CI: 0.10-6.64) and the other SUA quartiles with elevated ALT were null in women.

CONCLUSION

Our findings suggest that the relationship between each SUA level and elevated ALT may differ by sex among military young adults. The mechanism for the sex difference requires further investigations.

Association between mild anemia and physical fitness in a military male cohort: The CHIEF study

Anemia defined as reduced hemoglobin levels of red blood cells may carry less oxygen to skeletal muscle and impair physical performance. Previous studies have shown that exercise intolerance was related to moderate or severe anemia, however, the relationship to mild anemia was unknown. We investigated the cross-sectional association of mild anemia defined as a hemoglobin level of 10.0-13.9 g/dL with physical fitness in 3,666 military young males in Taiwan in 2014. Aerobic fitness was evaluated by 3000-meter run test, and anaerobic fitness was evaluated by 2-minute sit-ups and 2-minute push-ups, respectively. Multiple logistic regressions for the best 10% and the worst 10% performers were used to determine the relationship. There were 343 mild anemic males in whom 47.8% were microcytic anemia and 3,323 non-anemic males for the analysis. The multiple logistic regression shows that as compared with non-anemic males, mild anemic males were more likely to be the worst 10% performers in the 3000-meter run test (odds ratios (OR) and 95% confidence intervals: 1.47, 1.01-2.14) after adjusting for age, service specialty, body mass index, waist size, mean blood pressure, unhealthy behaviors, lipid profiles, and exercise frequency. On the contrary, mild anemic males had higher possibility to be the best 10% performers in the 2-minute push-ups test (OR: 1.48, 1.08-2.04). However, there was no association between mild anemia and 2-minute sit-ups. Our findings suggest that unspecified mild anemia might be associated with lower cardiorespiratory fitness but not with anaerobic fitness in physically active military males.

Association of electrocardiographic left and right ventricular hypertrophy with physical fitness of military males: The CHIEF study

AIM

To investigate the association of electrocardiographic (ECG) left and/or right ventricular hypertrophy (LVH and RVH) with physical fitness of military males.

METHODS

We used a military cohort of 2587 males, who were on average 29.1 years of age, from the cardiorespiratory fitness and hospitalization events in armed forces (CHIEF) study in Taiwan for the analysis. Isolated ECG-LVH (n = 779) was diagnosed by either the Sokolow-Lyon or Cornell voltage criteria. Isolated ECG-RVH (n = 234) was defined by either the Sokolow-Lyon or Myers et al. voltage criteria. Combined ECG-LVH/RVH (n = 140) was defined as those who met the voltage criteria for both LVH and RVH. The other ECGs were defined as unaffected (n = 1434). Physical fitness was evaluated by the upper and lower 16% exercise performance (beyond 1-standard deviation) in 3000-meter run, 2-minute sit-ups, and 2-minute push-ups. All procedures were standardized and monitored by unified computerized scoring systems. A multiple logistic regression was used to determine the relationship.

RESULTS

Compared with unaffected participants, those with an isolated ECG-LVH were tended to have a better 3000-meter run performance (odds ratio (OR) and 95% confidence intervals: 1.22 [0.99-1.50], p-value = 0.064) after adjusting for age, service specialty, body mass index, mean blood pressure, smoking status, alcohol intake, hemoglobin level, and exercise frequency. By contrast, those with an isolated ECG-RVH were tended to have a worse 2-minute sit-up performance (OR: 1.46 [0.99-2.16], p-value = 0.054).

CONCLUSION

Military males with ECG-LVH and/or ECG-RVH compared to unaffected participants may have diverse exercise performances. However, these observations narrowly failed to reach statistical significance.

Association of betel nut chewing with exercise performance in a military male cohort: the CHIEF study

INTRODUCTION

Betel nut chewing may cause obesity, neurohormonal activation and inflammation, possibly impairing exercise performances.

METHODS

We examined the cross-sectional association in 4388 military male adults aged 18-50 years from the cardiorespiratory fitness in armed forces study in Taiwan between 2013 and 2014. The status of betel nut chewing was classified as current and former/never based on each participant's response to a questionnaire. Physical fitness was evaluated by three basic exercise tests including 3000 m running, 2 min sit-ups and 2 min push-ups. Multiple logistic regression for the best 10% and the worst 10% performers in each exercise, and linear regression were used to determine the relationship.

RESULTS

There were 564 current chewers and 3824 non-current chewers for the analysis. The linear regression shows that current betel nut chewing was positively correlated with 3000 m running duration (r=0.37, p=0.042) after adjusting for age, service specialty, body mass index, exercise frequency and alcohol intake. In addition, the logistic regression shows that as compared with non-current chewers, current chewers had lower odds of being the top 10% performers in 2 min push-ups and higher odds of being the bottom 10% performers in 2 min sit-ups (ORs and 95% CIs: 0.71 (0.50 to 0.99) and 1.32 (1.00 to 1.75), respectively). However, the associations between betel nut chewing and physical fitness were all insignificant after further adjusting for current smoking.

CONCLUSIONS

Our findings suggest that the impairment of physical fitness associated with betel nut chewing of military young men might be mainly mediated or moderated by the coexisted cigarette smoking.

Sex-Specific Association between Metabolic Abnormalities and Elevated Alanine Aminotransferase Levels in a Military Cohort: The CHIEF Study

The association of metabolic syndrome (MetS) components with elevated serum alanine aminotransferase (ALT) levels, a marker of hepatic injury, may differ between men and women. However, the sex-specific association in a military young population which has a low prevalence of MetS was unclear. We conducted a cross-sectional examination in 6738 men and 766 women, aged 18-50 years, from the cardiorespiratory fitness study in armed forces (CHIEF) in eastern Taiwan. The components of MetS were defined according to the updated International Diabetes Federation (IDF) ethnic criteria for Asians. Elevated ALT levels were defined as ≥40 U/L for both sexes and ≥30 U/L for women alternatively. Multivariate logistic regression analysis was performed to determine the sex-specific association between MetS components and elevated ALT. The prevalence of MetS and elevated ALT in men were 11.9% and 12.7% respectively, and in women were 3.5%, and 3.8% respectively. In men, high-density lipoprotein < 40 mg/dL, blood pressures ≥ 130/85 mmHg, serum triglycerides ≥ 150 mg/dL, and waist size ≥ 90 cm were associated with elevated ALT (odds ratios (OR) and 95% confidence intervals: 1.59 (1.34-1.90), 1.40 (1.19-1.65), 2.00 (1.68-2.39), and 1.68 (1.38-2.04); all p < 0.001); whereas in women, only fasting plasma glucose ≥ 100 mg/dL was associated with elevated ALT ≥ 40 U/L (OR: 7.59 (2.35-24.51), p = 0.001) and ALT ≥ 30 U/L (2.67 (0.89-7.95), p = 0.08). Our findings suggest that the relationship between metabolic abnormalities and elevated ALT may differ by sex, possibly due to the MetS more prevalent in young adult men than in women.

Chronic hepatitis B, nonalcoholic steatohepatitis and physical fitness of military males: CHIEF study

AIM

To investigate the association of chronic hepatitis B and nonalcoholic steatohepatitis with physical fitness in a Taiwanese military male cohort.

METHODS

We made a cross-sectional examination of this association using 3669 young adult military males according to cardiorespiratory fitness and hospitalization events recorded in the Taiwan Armed Forces study. Cases of chronic hepatitis B (n = 121) were defined by personal history and positive detection of hepatitis B surface antigen. Cases of nonalcoholic steatohepatitis (n = 129) were defined by alanine transaminase level > 60 U/L, liver ultrasound finding of steatosis, and absence of viral hepatitis A, B or C infection. All other study participants were defined as unaffected (n = 3419). Physical fitness was evaluated by performance in 3000-m run, 2-min sit-ups, and 2-min push-ups exercises, with all the procedures standardized by a computerized scoring system. Multiple linear regression analysis was used to determine the relationship.

RESULTS

Chronic hepatitis B negatively correlated with 2-min push-up numbers (β = -2.49, P = 0.019) after adjusting for age, service specialty, body mass index, systolic and diastolic blood pressures, current cigarette smoking, alcohol intake status, serum hemoglobin, and average weekly exercise times. Nonalcoholic steatohepatitis was borderline positively correlated with 3000-m running time (β = 11.96, P = 0.084) and negatively correlated with 2-min sit-up numbers (β = -1.47, P = 0.040).

CONCLUSION

Chronic hepatitis B viral infection and nonalcoholic steatohepatitis affects different physical performances in young adult military males, and future study should determine the underlying mechanism.

A comparison of Cornell and Sokolow-Lyon electrocardiographic criteria for left ventricular hypertrophy in a military male population in Taiwan: the Cardiorespiratory fitness and HospItalization Events in armed Forces study

BACKGROUND

The Cornell and Sokolow-Lyon electrocardiography (ECG) criteria have been widely used for diagnosing left ventricular hypertrophy (LVH) in patients with hypertension. However, the correlations of these ECG criteria with LVH were rarely compared in military members who received rigorous training, particularly of the Asian male population.

METHODS

We compared the Cornell voltage and product criteria with the Sokolow-Lyon criteria for the echocardiographic LVH in 539 military male members, ages 18-50 years and free of hypertension in the Cardiorespiratory fitness and HospItalization Events in armed Forces (CHIEF) study in Taiwan. Pearson's correlation coefficient was used to determine the association of each ECG criterion with the index of left ventricular mass (LVM, g)/height (m)^2.7. The sensitivities and specificities were estimated using a receiver-operating characteristics (ROC) curve in relation to the echocardiographic LVH which was defined as LVM index ≥49 g/m^2.7.

RESULTS

The correlations of the Cornell voltage and product criteria (r=0.24 and 0.26 respectively, both P<0.0001) were stronger than that of the Sokolow-Lyon criteria (r=0.049 and 0.095, and P=0.26 and 0.03 respectively) with the LVM index. Similarly the performances of the Cornell voltage and product criteria for the echocardiographic LVH [area under curve (AUC): 0.66 and 0.68, both P<0.0001] were superior to that of the Sokolow-Lyon criteria (AUC: 0.54 and 0.53, both P>0.1) in the area under the ROC curve analysis.

CONCLUSIONS

The Cornell ECG criteria for the echocardiographic LVH had better performance than the Sokolow-Lyon criteria in a young military male cohort in Taiwan.

Association between electrocardiographic and echocardiographic right ventricular hypertrophy in a military cohort in Taiwan: The CHIEF study: ECG criteria for RVH

We compared electrocardiographic and echocardiographic right ventricular hypertrophy (RVH) in 264 military members in Taiwan. The correlations of the Myers et al. and Sokolow-Lyon criteria with RV wall thickness were low (r < 0.1). Our data supported the American guidance that RVH voltage criteria violations should not receive further echocardiographic investigation.