Susumu S. Sawada

Importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign: a scientific statement from the American Heart Association

Mounting evidence has firmly established that low levels of cardiorespiratory fitness (CRF) are associated with a high risk of cardiovascular disease, all-cause mortality, and mortality rates attributable to various cancers. A growing body of epidemiological and clinical evidence demonstrates not only that CRF is a potentially stronger predictor of mortality than established risk factors such as smoking, hypertension, high cholesterol, and type 2 diabetes mellitus, but that the addition of CRF to traditional risk factors significantly improves the reclassification of risk for adverse outcomes. The purpose of this statement is to review current knowledge related to the association between CRF and health outcomes, increase awareness of the added value of CRF to improve risk prediction, and suggest future directions in research. Although the statement is not intended to be a comprehensive review, critical references that address important advances in the field are highlighted. The underlying premise of this statement is that the addition of CRF for risk classification presents health professionals with unique opportunities to improve patient management and to encourage lifestyle-based strategies designed to reduce cardiovascular risk. These opportunities must be realized to optimize the prevention and treatment of cardiovascular disease and hence meet the American Heart Association’s 2020 goals.

Calf circumference as a surrogate marker of muscle mass for diagnosing sarcopenia in Japanese men and women

To examine the relationship between calf circumference and muscle mass, and to evaluate the suitability of calf circumference as a surrogate marker of muscle mass for the diagnosis of sarcopenia among middle‐aged and older Japanese men and women.

Cardiorespiratory fitness and cancer mortality in Japanese men: A prospective study

PURPOSE Limited data are available on the relationship between cardiorespiratory fitness and cancer mortality. We evaluated the cardiorespiratory fitness and risk of cancer mortality in Japanese men. METHODS A total of 9039 men (19-59 yr) who were given a submaximal exercise test and a health examination between 1982 and 1988 and were followed for mortality up to 1999. Cardiorespiratory fitness was measured using a cycle ergometer test, and maximal oxygen uptake was estimated. RESULTS The mean follow-up period was slightly more than 16 yr, producing a total of 148,491 person-years of observation. There were 231 deaths, with 123 deaths due to cancer. Relative risk (RR) and 95% confidence interval (95%CI) for cancer mortality were obtained using the Cox proportional hazards model. Taking into consideration age, systolic blood pressure, body mass index, smoking habit, and alcohol habit and using the lowest physical fitness group as the reference, the RR (95% CI) for increasing quartiles of fitness were 0.75(0.48-1.16), 0.43(0.25-0.74) and 0.41(0.23-0.74); P < 0.001 for trend. CONCLUSION Low cardiorespiratory fitness is associated with cancer mortality in Japanese men.

Long-term trends in cardiorespiratory fitness and the incidence of type 2 diabetes.

OBJECTIVE Whereas single assessments of cardiorespiratory fitness have been shown to predict lower incidence of type 2 diabetes, there are no data on long-term trends in fitness and risk. We investigated the relationship between long-term trends in fitness and the incidence of type 2 diabetes. RESEARCH DESIGN AND METHODS A cohort of 4,187 Japanese men free of diabetes completed annual health checkups and fitness tests for estimated maximal oxygen uptake at least four times over 7 years (1979–1985). We modeled the trend in fitness over 7 years for each man using simple linear regression. Men were then divided into quartiles based on the regression coefficient (slope) from the model. During the follow-up period (1985–1999), 274 men developed diabetes. Hazard ratios (HRs) and 95% CIs for the incidence of diabetes were obtained using the Cox proportional hazards model. RESULTS Men in the lowest quartile of the distribution decreased in fitness over the 7 years (median slope −1.25 ml/kg/min), whereas men in the highest quartile increased in fitness (median slope 1.33 ml/kg/min). With adjustment for age, initial fitness level, BMI, systolic blood pressure, cigarette smoking, alcohol intake, and a family history of diabetes and use of the lowest quartile, the HRs (95% CI) for the second through fourth quartiles were 0.64 (0.46–0.89), 0.40 (0.27–0.58), and 0.33 (0.21–0.50), respectively (Ptrend < 0.001). CONCLUSIONS These results indicate that the long-term trend in fitness is a strong predictor of the incidence of type 2 diabetes in Japanese men.

FIVE YEAR PROSPECTIVE STUDY ON BLOOD PRESSURE AND MAXIMAL OXYGEN UPTAKE

1. The relationship between physical fitness (maximal oxygen uptake Vo2max) and incidence of hypertension was investigated through a prospective study for a total of 16525 human‐years of observation.

Associations between Cardiorespiratory Fitness and Health-Related Quality of Life

BackgroundThere is limited data examining the association between cardiorespiratory fitness (CRF) and health related quality of life (HRQOL) in healthy young adults. We examined the association between CRF and the HRQOL Physical Component Summary (PCS) and Mental Component Summary (MCS) scores in apparently healthy males in the United States Navy.MethodsA total of 709 males (18–49 yr) performed a submaximal exercise test and HRQOL assessment (SF-12v2™) between 2004–2006. CRF level was classified into fourths depending on age distribution with the lowest fitness quartile serving as the referent group. PCS and MCS scores ≥ 50 were defined as above the norm. Logistic regression was used to obtain odds ratios (OR) and 95% confidence intervals (CI). ResultsThe age-standardized prevalence of above the norm scores was lowest in the referent CRF quartile, PCS 56.6% and MCS 45.1%. After adjusting for age, systolic blood pressure, body mass index, smoking habit, alcohol habit and using the lowest CRF group as the reference, the OR (95% CI) for PCS scores above the norm across the fitness quartiles (P < 0.003 for trend) were 1.51(0.94–2.41), 2.24(1.29–3.90), and 2.44 (1.30–4.57); For MCS the OR (95% CI) were across the fitness quartiles (P trend < 0.001) 2.03(1.27–3.24), 4.53(2.60–7.90), 3.59(1.95–6.60).ConclusionAmong males in the United States Navy relative higher levels of CRF are associated with higher levels of HRQOL.

Associations of sedentary behavior and physical activity with psychological distress: a cross-sectional study from Singapore.

BackgroundEmerging evidence suggests the adverse association between sedentary behaviour (SB) with physical and mental health, but few studies have investigated the relationship between volume of physical activity and psychological distress. The present study examined the independent and interactive associations of daily SB and weekly level of moderate to vigorous physical activity (MVPA) with psychological distress in a multi-ethnic Asian population.MethodsDe-identified data of 4,337 adults (18–79 years old) on sedentary behaviors, physical activity patterns, psychological distresses, and other relevant variables were obtained from the Singapore Ministry of Health’s 2010 National Health Survey. Psychological distress was assessed using General Health Questionnaire-12 (GHQ-12), whereas total daily SB and total weekly volume (MET/minutes) of MVPA were estimated using the Global Physical Activity Questionnaire version 2 (GPAQ v2). Multivariate logistic regression analyses were carried out to estimate the odds ratios (95% confidence intervals) of the independent and interactive relationships of SB and MVPA with prevalence of psychological distress.ResultsThe category of high SB was positively associated with increased odds (OR = 1.29, 1.04-1.59) for psychological distress, whereas the category of active was inversely associated with lower odds (OR = 0.73, 0.62-0.86) for psychological distress. Multivariate analyses for psychological distress by combined daily SB and weekly MVPA levels showed inverse associations between middle SB and active categories (OR = 0.58, 0.45 - 0.74) along with low SB and active categories (OR = 0.61, 0.47-0.80).ConclusionsThe present population-based cross-sectional study indicated that in the multi-ethnic Asian society of Singapore, a high level of SB was independently associated with psychological distress and meeting the recommended guidelines for physical activity along with ≤ 5 h/day of SB was associated with the lowest odds of psychological distress.

Dose–response relationship between sports activity and musculoskeletal pain in adolescents

Abstract Physical activity has multiple health benefits but may also increase the risk of developing musculoskeletal pain (MSP). However, the relationship between physical activity and MSP has not been well characterized. This study examined the dose–response relationship between sports activity and MSP among adolescents. Two school-based serial surveys were conducted 1 year apart in adolescents aged 12 to 18 years in Unnan, Japan. Self-administered questionnaires were completed by 2403 students. Associations between time spent in organized sports activity and MSP were analyzed cross-sectionally (n = 2403) and longitudinally (n = 374, students free of pain and in seventh or 10th grade at baseline) with repeated-measures Poisson regression and restricted cubic splines, with adjustment for potential confounders. The prevalence of overall pain, defined as having pain recently at least several times a week in at least one part of the body, was 27.4%. In the cross-sectional analysis, sports activity was significantly associated with pain prevalence. Each additional 1 h/wk of sports activity was associated with a 3% higher probability of having pain (prevalence ratio = 1.03, 95% confidence interval = 1.02-1.04). Similar trends were found across causes (traumatic and nontraumatic pain) and anatomic locations (upper limbs, lower back, and lower limbs). In longitudinal analysis, the risk ratio for developing pain at 1-year follow-up per 1 h/wk increase in baseline sports activity was 1.03 (95% confidence interval = 1.02-1.05). Spline models indicated a linear association (P < 0.001) but not a nonlinear association (P ≥ 0.45). The more the adolescents played sports, the more likely they were to have and develop pain.

A Fit-Fat Index for Predicting Incident Diabetes in Apparently Healthy Men: A Prospective Cohort Study

Background The purpose of this study was to examine the impact of combined cardiorespiratory fitness and waist-to-height ratio in the form of a fit-fat index on incident diabetes risk. Additionally, the independent predictive performance of cardiorespiratory fitness, waist-to-height ratio, and body mass index also were estimated and compared. Methods This was a prospective cohort study of 10,381 men who had a normal electrocardiogram and no history of major chronic disease at baseline from 1979 to 2005. Random survival forest models and traditional Cox proportional hazards models were used to predict diabetes at 5-, 10-, and 15-year incidence horizons. Results Overall, 4.8% of the participants developed diabetes. Receiver operating characteristic curve analyses for incidence risk demonstrated good discrimination using random survival forest models across fitness and fatness measures; Cox models were poor to fair. The differences between fitness and fatness measures across horizons were clinically negligible. Smoothed random survival forest estimates demonstrated the impact of each fitness and fatness measure on incident diabetes was intuitive and graded. Conclusions Although fitness and fatness measures showed a similar discriminative ability in predicting incident diabetes, unique to the study was the ability of the fit-fat index to demonstrate a better indication of incident risk when compared to fitness or fatness alone. A single index combining cardiorespiratory fitness and waist-to-height ratio may be more useful because it can indicate improvements in either or both of the measures.

Body Mass Index and Kidney Stones: A Cohort Study of Japanese Men

BACKGROUND In Japan, the incidence of kidney stones has increased markedly in recent decades. Major causes of kidney stones remain unclear, and limited data are available on the relationship between overweight/obesity and the incidence of kidney stones. We therefore evaluated body mass index (BMI) and the incidence of kidney stones in Japanese men. METHODS Of the workers at a gas company, 5984 males aged 20-40 years underwent a medical examination in 1985 (baseline). This study includes 4074 of the men, who were free of kidney stones at baseline and underwent a second medical examination performed between April 2004 and March 2005. BMI was calculated from measured height and weight in 1985, and men were categorized into tertiles. The development of kidney stones during follow-up was based on self-reports from questionnaires at the second medical examination. RESULTS The average duration of follow-up was 19 years, with 258 participants developing kidney stones during this period. Using the lowest BMI (1st tertile) group as a reference, the hazard ratios (95% confidence intervals [CIs]) for the 2nd and 3rd BMI tertiles were: 1.26 (95% CI, 0.92-1.73) and 1.44 (95% CI, 1.06-1.96), respectively (P for trend = 0.019). After additionally adjusting for potential confounders, such as age, systolic blood pressure, cardiorespiratory fitness, cigarette smoking, and alcohol consumption, the hazard ratios were 1.28 (95% CI, 0.93-1.76) and 1.41 (95% CI, 1.02-1.97), respectively (P for trend = 0.041). CONCLUSIONS These results suggest that increased BMI is a risk factor for kidney stones in Japanese men.