Estimated Cardiorespiratory Fitness and Metabolic Risks.

This review focuses on the emerging evidence for the association between non-exercise fitness testing, estimated cardiorespiratory fitness (eCRF), and metabolic risk factors. Given the challenges associated with directly measuring cardiorespiratory fitness (CRF) in large populations, eCRF presents a practical alternative for predicting metabolic health risks. A literature search identified seven relevant cohort studies from 2020 to 2024 that investigated the association of eCRF with hypertension, hyperglycemia, dyslipidemia, and obesity. This review consistently demonstrates an inverse relationship between higher eCRF and a lower incidence of metabolic risks, which is in line with CRF cohort studies. It highlights the importance of low eCRF as a primordial indicator for metabolic risks and underscores the potential for broader application. Future research directions should include exploring eCRF's predictive ability across diverse populations and health outcomes and testing its real-world applicability in healthcare and public health settings.

Association between Estimated Cardiorespiratory Fitness and Abnormal Glucose Risk: A Cohort Study.

BACKGROUND: Cardiorespiratory fitness (CRF) is a predictor of chronic disease that is impractical to routinely measure in primary care settings. We used a new estimated cardiorespiratory fitness (eCRF) algorithm that uses information routinely documented in electronic health care records to predict abnormal blood glucose incidence. METHODS: Participants were adults (17.8% female) 20-81 years old at baseline from the Aerobics Center Longitudinal Study between 1979 and 2006. eCRF was based on sex, age, body mass index, resting heart rate, resting blood pressure, and smoking status. CRF was measured by maximal treadmill testing. Cox proportional hazards regression models were established using eCRF and CRF as independent variables predicting the abnormal blood glucose incidence while adjusting for covariates (age, sex, exam year, waist girth, heavy drinking, smoking, and family history of diabetes mellitus and lipids). RESULTS: Of 8602 participants at risk at baseline, 3580 (41.6%) developed abnormal blood glucose during an average of 4.9 years follow-up. The average eCRF of 12.03 ± 1.75 METs was equivalent to the CRF of 12.15 ± 2.40 METs within the 10% equivalence limit. In fully adjusted models, the estimated risks were the same (HRs = 0.96), eCRF (95% CIs = 0.93-0.99), and CRF (95% CI of 0.94-0.98). Each 1-MET increase was associated with a 4% reduced risk. CONCLUSIONS: Higher eCRF is associated with a lower risk of abnormal glucose. eCRF can be a vital sign used for research and prevention.

The Association of Sudarshan Kriya Yoga with Happiness: A Case-Control Observational Study from Singapore.

Happiness is a complex subjective experience that is essential to societal progress. This study investigated the association between Sudarshan Kriya Yoga (SKY) and subjective happiness in Singapore. Subjective happiness data were collected from a convenience sample (N = 733) comprised of 2 groups: SKY (n = 385) and non-SKY (n = 348) practitioners. SKY was categorized into non-, monthly, weekly, and daily practitioners and happiness was categorized into lower, middle and higher tertile groups. Confounding variables included age, gender, ethnicity, marital status, education level, body mass index (BMI), smoking status, alcohol consumption and self-reported health. Daily SKY participation was positively associated with a 2-fold higher likelihood of being happier in a multivariate regression analysis. The trend analysis showed that as SKY frequency increases, the odds of being happier increases. These findings help generate the hypothesis that yogic breathing may promote happiness. Further experimental and prospective investigations are warranted.

Estimating Cardiorespiratory Fitness Without Exercise Testing or Physical Activity Status in Healthy Adults: Regression Model Development and Validation.

BACKGROUND: Low cardiorespiratory fitness (CRF) is an independent predictor of morbidity and mortality. Most health care settings use some type of electronic health record (EHR) system. However, many EHRs do not have CRF or physical activity data collected, thereby limiting the types of investigations and analyses that can be done. OBJECTIVE: This study aims to develop a nonexercise equation to estimate and classify CRF (in metabolic equivalent tasks) using variables commonly available in EHRs. METHODS: Participants were 42,676 healthy adults (female participants: n=9146, 21.4%) from the Aerobics Center Longitudinal Study examined from 1974 to 2005. The nonexercise estimated CRF was based on sex, age, measured BMI, measured resting heart rate, measured resting blood pressure, and smoking status. A maximal treadmill test measured CRF. RESULTS: After conducting nonlinear feature augmentation, separate linear regression models were used for male and female participants to calculate correlation and regression coefficients. Cross-classification of actual and estimated CRF was performed using low CRF categories (lowest quintile, lowest quartile, and lowest tertile). The multiple correlation coefficient (R) was 0.70 (mean deviation 1.33) for male participants and 0.65 (mean deviation 1.23) for female participants. The models explained 48.4% (SE estimate 1.70) and 41.9% (SE estimate 1.56) of the variance in CRF for male and female participants, respectively. Correct category classification for low CRF (lowest tertile) was found in 77.2% (n=25,885) of male participants and 74.9% (n=6,850) of female participants. CONCLUSIONS: The regression models developed in this study provided useful estimation and classification of CRF in a large population of male and female participants. The models may provide a practical method for estimating CRF derived from EHRs for population health research.

Satisfaction of Patients Who Received Breast-Conserving Surgery Using the Suture Scaffold Technique: A Single-Institution, Cross-Sectional Study.

BACKGROUND: Optimal cosmetic results after breast-conserving surgery (BCS) improve patient satisfaction. The suture scaffold technique (SST) is a breast reconstruction technique that all breast surgeons can perform without any extensive training in plastic surgery. OBJECTIVE: We aimed to investigate patient satisfaction after BCS and compare blood loss and operative duration between the SST, breast glandular flap technique (BGFT), and no oncoplastic technique (NOT). METHODS: This was a prospective, single-center, cross-sectional study. All patients who underwent BCS from August 2017 to September 2019 in our institution were included, with the exception of those with cT3 tumors or those who underwent nipple excision or bilateral breast surgery. The BREAST-Q™ was used to survey the patients, and the raw sum scale scores of the BREAST-Q™ were converted into BREAST-Q scores. RESULTS: Overall, we identified 421 eligible patients. The NOT was used in 47 (11.1%) patients, the BGFT was used in 231 (54.8%) patients, and the SST was used in 143 (33.9%) patients. In the univariable model, the BGFT and the SST had higher BREAST-Q scores than the NOT, while in the multivariable model, the SST had significantly higher BREAST-Q scores than the NOT (ß = +7.7, 95% confidence interval [CI] 0.9-13.7; p = 0.01). Blood loss was significantly less with the SST compared with the BGFT (ß = -4.4, 95% CI -7.3 to -1.4), and there was no difference in operative duration between the methods. CONCLUSIONS: Patient satisfaction with the SST was higher than with the NOT and was similar to the BGFT. The SST is an oncoplastic technique that all breast surgeons can perform and which requires comparable blood loss and operative duration in the NOT.

Accuracy of Non-Exercise Estimated Cardiorespiratory Fitness in Japanese Adults.

Cardiorespiratory fitness (CRF) is an independent predictor of morbidity and mortality. In Japan, annual physical exams are mandatory in workplace settings, and most healthcare settings have electronic medical records (EMRs). However, in both settings, CRF is not usually determined, thereby limiting the potential for epidemiological investigations using EMR data. PURPOSE: To estimate CRF (mL/kg/min) using variables commonly recorded in EMRs. METHODS: Participants were 5293 Japanese adults (11.7% women) who completed an annual physical exam at a large gas company in Tokyo, Japan, in 2004. The mean age was 48.3 ± 8.0 years. Estimated CRF (eCRF) was based on age, measured body mass index, resting heart rate, systolic and diastolic blood pressure, and smoking. Measured CRF was determined by a submaximal cycle ergometer graded exercise test. RESULTS: Regression models were used for males and females to calculate Pearson's correlation and regression coefficients. Cross-classification of measured CRF and eCRF was conducted using the lowest quintile, quartile, and tertile as the unfit categories. R's for eCRF were 0.61 (MD 4.41) for men and 0.64 (MD 4.22) for women. The overall accuracy level was reasonable and consistent across models, yet the unfit lower tertile model provided the best overall model when considering the positive predictive value and sensitivity. CONCLUSION: eCRF may provide a useful method for conducting investigations using data derived from EMRs or datasets devoid of CRF or physical activity measures.

Association Between Sudarshan Kriya Yoga and Healthy Lifestyle Practices Among Working Adults: A Cross-Sectional Study from Singapore.

Objectives: There is a paucity of research on the association between yogic breathing and healthy lifestyle factors in working adults. Also, there is very little information about the frequency of yogic breathing practice and its benefits. The authors investigated the relationship between Sudarshan Kriya Yoga (SKY) frequency and the likelihood of leading a healthier lifestyle among practitioners and nonpractitioners. Design: Cross-sectional investigation on non-SKY and SKY practitioners, SKY was categorized into non-, monthly, weekly, and daily practitioners. Confounding variables included age, gender, ethnicity, marital status, and education level. A multivariate logistic regression model was used to compare practice frequencies with the odds of having a healthier lifestyle. Settings: Community centers, community events, workplaces, and universities throughout Singapore Subjects: Of the 531 working adults (54.8% female), 50.1% had a healthier lifestyle ≥ 4 healthy lifestyle factors). Outcome Measure: Having a healthier lifestyle was defined as having ≥ 4 healthy lifestyle factors out of seven (smoking, alcohol, diet, exercise, sleep, stress, and weight). Results: Multivariate analysis demonstrated that those who practiced SKY ≥ 4 days/week had significantly higher odds of having a healthier lifestyle (odds ratio = 3.62; 95% confidence interval = 2.10-6.23). The p for trend analysis demonstrated that as the frequency of practice increased the likelihood of having a healthier lifestyle also increased ( p < 0.001). Conclusion: The practice of yogic breathing may promote a healthier lifestyle in working adults. Further experimental and longitudinal investigations are warranted.

The association of fitness and fatness with intermediate hyperglycemia incidence in women: A cohort study.

The purpose of this study was to examine the associations of cardiorespiratory fitness, general adiposity, and central adiposity with incident intermediate hyperglycemia (IH) in women. We conducted a prospective cohort study of 1534 women aged 20-79 years old who had an annual health check-up with no history of major chronic diseases. At baseline, fitness was assessed by a Balke graded exercise test, and the estimated metabolic equivalents were used to create quartile groups. Women were also grouped based on their body mass index (<25 kg/m2, 25-29.9 kg/m2, and ≥ 30 kg/m2) and waist-to-height ratio (≥0.50 or < 0.50). Cox proportional hazards models were conducted to assess the association of fitness and fatness variables with incident IH defined as fasting glucose of 5.6-6.9 mmol/L. Overall, 18.1% (n = 277) of the women developed IH during an average follow-up of 5.06 years. Fitness, body mass index, and waist-to-height ratio at baseline were the independent predictors of the IH incidence in separate age-adjusted models; yet when all three variables were included in the same model along with confounding variables, only fitness remained significant and demonstrated a clear inverse association with incident IH (P-for-trend <0.001). Health promotion efforts should focus on improving fitness for the prevention of IH in women.

The association of Sudarshan Kriya Yoga frequency with sleep quality: a cross-sectional study from Singapore.

PURPOSE: There is a dearth of evidence for the relationship between yogic breathing and sleep quality. Even less is known about practice frequency and benefit. We investigated the association of Sudarshan Kriya Yoga frequency with sleep quality amongst adult practitioners. METHODS: In a cross-sectional investigation on adult practitioners of Sudarshan Kriya Yoga in Singapore, the Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. Sleep quality was examined across three categories of practice frequency (monthly, weekly, daily). A multivariate logistic regression model was used to determine association. RESULTS: Of 385 adults (241 women), the mean age (SD) was 42.5 (9.9) years. In total, 32% of the sample (n = 124) was identified as having poor SQ. After adjusting for study covariates, independent analyses revealed an inverse association for higher frequency of practice and lower odds of poor SQ (OR = 0.52; 95% CI = 0.28-0.94). The p for trend was 0.03. CONCLUSION: The practice of yogic breathing may benefit sleep quality. Further experimental investigations are warranted.

Examining the day-to-day bidirectional associations between physical activity, sedentary behavior, screen time, and sleep health during school days in adolescents.

BACKGROUND: Adolescence is a vulnerable period for experiencing poor sleep health. Growing studies have demonstrated lifestyle behaviors including physical activity (PA), screen time (SCT), and sedentary behaviors (SED) as the potential factors associated with sleep health in adolescents; yet, the evidence is inconclusive and the directionality of temporal associations across school days are not well understood. This study examined the day-to-day bidirectional associations of lifestyle behaviors with sleep health parameters in adolescents. METHODS: A total of 263 adolescents (58% boys) in 6th - 8th grades wore an accelerometer for 24-hour across the three consecutive school days and completed recording SCT in time-diary and answering sleep quality (SQ) questions for each day. Sleep-wake patterns as well as time spent in moderate- and vigorous-intensity PA (MVPA) and SED were objectively quantified from the wrist-worn accelerometry data across the two segments of the day (during and after school hours). Mixed model analyses were conducted to test bidirectional associations between lifestyle factors and sleep health parameters in each temporal direction across the days. Additionally, indirect associations across the days were tested using an autoregressive cross-lagged model analysis in the framework of path analysis. RESULTS: MVPA minutes in a day did not predict sleep health parameters that night. The bidirectional associations were partially observed between SED and sleep health, but the significance and direction of the associations largely varied by the time segment of a day as well as types of sleep health parameters. Additionally, greater SCT during the day was associated with lower SQ that night (b = -0.010; P = .018), and greater SQ was associated with greater MVPA during school hours (b = 6.45; P = .028) and lower SED after school hours (b = -39.85; P = .029) the next day. Lastly, there were significant indirect associations of SCT with sleep health parameters across the days indicating multi-day lagged effects of SCT on sleep health the later nights. CONCLUSION: This study highlights the importance of lowering SCT for better sleep health in adolescents during school days. Additionally, perceived SQ is shown to be a potential significant predictor promoting healthy behaviors the next day independent of sleep-wake patterns. Further studies are warranted to confirm the observed temporal associations between SCT, SQ, and behavioral outcomes in this vulnerable population.

Clarifying differences in viewpoints between multiple healthcare professionals during discharge planning assessments when discharging patients from a long-term care hospital to home.

Comprehensive discharge planning provided by interprofessional collaboration is critical for discharging patients from hospitals to home. For effective interprofessional discharge planning, the evaluation that clarifies the differences in assessment viewpoints between various healthcare professionals is needed. This study aimed to clarify the assessment viewpoints of multiple healthcare professional groups when discharging patients from a long-term care hospital (LTCH) to home. We reviewed 102 medical records from an LTCH in Japan, extracted descriptions of discharge planning assessments written by 3 doctors, 13 nurses, 3 physical therapists, 13 care workers, and 2 social workers, linked these to the International Classification of Functioning, Disability and Health, and conducted the statistical analysis. Doctors and nurses significantly focused on "Body Functions". Physical therapists and care workers significantly focused on "Activities and Participation". Social workers significantly focused on "Environmental Factors". We also identified the factors less or missing from assessments in the clinical field of the LTCH. Our findings could be contributed as a base of knowledge to foster a better understanding of different healthcare professionals' assessment viewpoints. The further development of comprehensive discharge planning assessment tools, service programs, and research on discharge planning methods that could contribute to effective interprofessional discharge planning is needed.

Is Less Sedentary Behavior, More Physical Activity, or Higher Fitness Associated with Sleep Quality? A Cross-Sectional Study in Singapore.

OBJECTIVES: To examine the independent, joint, and fully combined associations of sedentary behavior (SB), moderate-to-vigorous physical activity (MVPA), and cardiorespiratory fitness (CRF) with the odds of poor sleep quality (SQ). METHODS: We performed a secondary data analysis on 757 working adults (male = 345) in Singapore, with an average age of 35.2 years. The Pittsburgh Sleep Quality Index was used to assess SQ. Objectively measured MVPA and SB were each obtained using an accelerometer. A non-exercise prediction equation was used to estimate CRF. Logistic regression models were used to determine associations. RESULTS: In total, 13.2% of the sample (n = 100) was identified as having poor SQ. After adjusting for study covariates, independent analyses revealed a clear inverse association for higher CRF and lower odds of poor SQ (OR = 0.50; 95% CI = 0.28-0.91). SB and MVPA demonstrated no independent associations. Joint associations revealed that odds of having poor SQ for those with low CRF was higher regardless of SB level and was further deteriorated by lower MVPA in the fully combined model. The fully combined model also demonstrated that those with lower SB, higher MVPA, and higher CRF had the lowest odds of having poor SQ (OR = 0.28; 95% CI = 0.10-0.78). CONCLUSIONS: Physical activity/exercise training programs that aim to improve CRF may be useful in lowering the odds or poor SQ in working adults.

Volume and Intensity of Stepping Activity and Cardiometabolic Risk Factors in a Multi-ethnic Asian Population.

The health benefits of objectively measured physical activity volume versus intensity have rarely been studied, particularly in non-western populations. The aim of this study was to investigate the association between cardiometabolic risk factors and stepping activity including; volume (step count), intensity (cadence) or inactivity (zero-steps/minute/day), in a multi-ethnic Asian population. Participants clinical data was collected at baseline and their physical activity was monitored for seven days, using an accelerometer (Actigraph GT3X+) in 2016. Tertiles (low, moderate, high) of the mean daily step count, peak one-minute, 30-min, 60-min cadences and time/day spent at zero-steps/minute were calculated. Adjusted linear regressions explored the association between stepping activity tertiles and cardiometabolic risk factors. A total of 635 participants (41% male, 67% Chinese, mean age 48.4 years) were included in the analyses. The mean daily step count was 7605 (median daily step count 7310) and 7.8 h of awake time per day were spent inactive (zero-steps/minute). A greater number of associations were found for step intensity than volume. Higher step intensity was associated with reduced body mass index (BMI), waist circumference, blood pressures and higher high-density lipoprotein (HDL). Future health promotion initiatives should consider the greater role of step intensity to reduce cardiometabolic risk.

Frequency of achieving a 'fit' cardiorespiratory fitness level and hypertension: a cohort study.

OBJECTIVES: Although maintaining cardiorespiratory fitness is encouraged to reduce the risk of hypertension, the level at, and length of time for which, individuals need to maintain fitness remains unclear. We examined the association between the frequency of achieving the recommended fitness levels of the 'Physical Activity Reference for Health Promotion 2013' and the risk of hypertension among Japanese men. METHODS: This cohort study was conducted in 6653 men without hypertension enrolled in 1986. Whether the participants' fitness level was equal to or exceeded the reference value (fit) or not (unfit) was determined. The frequency of achieving the recommended fitness level was calculated by counting the number of times the fitness level was achieved in 1980 through 1986. Incident hypertension was defined as the first visit with a SBP/DBP of at least 140/90 mmHg or self-reported antihypertensive medication use and was evaluated during annual health examinations from 1986 until 2009. RESULTS: During the follow-up period, 3630 men developed hypertension. The multivariable-adjusted hazard ratios (95% confidence interval) for incident hypertension comparing men with fit versus unfit at baseline was 0.79 (0.74-0.85). Moreover, the frequency of achieving the recommended fitness level was inversely associated with the incidence of hypertension. The risk of hypertension was lower among those who achieved three or more of the recommended levels (0.72 for three times to 0.62 for seven times). CONCLUSION: Achieving the fitness level recommended in the Japanese guideline three or more times during a 6-year period can be beneficial for the risk reduction of hypertension.

Stepping volume and intensity patterns in a multi-ethnic urban Asian population.

BACKGROUND: Accelerometer measured physical activity (PA) studies particularly in non-western populations are lacking. Therefore, this study investigated stepping activity in a multi-ethnic urban Asian population. METHODS: Adult participants from the Singapore Health Study 2 consented to accelerometer activity monitoring for 7-consecutive days. Mean daily step count, peak stepping intensity (i.e. cadence) over 1-min, 30-min and 60-min and time spent in each cadence band: 0 (non-movement), 1-19, 20-39, 40-59, 60-79, 80-99 and ≥ 100 steps/minute (moderate to vigorous PA) were calculated. RESULTS: A total of 713 participants (42% male, mean age 47.8 years) were included. Overall, the mean daily step count was 7549. Mean daily step count was significantly lower in Indians (7083 adjusted p = 0.02) but not Malays 7140 (adjusted p = 0.052) compared to Chinese (7745 steps). The proportion of Malays, Indians, and Chinese achieving < 5000 daily steps was 26%, 23% and 14%, respectively (p < 0.01). Regardless of ethnicity, approximately half of the recorded time was spent undertaking 0-steps/minute (7.9 h). CONCLUSIONS: Greater promotion of brisk walking is required in light of the low step volume and pace observed in this multi-ethnic Asian population. Ethnic differences in stepping activity were also identified which indicates a need for targeted ethnic specific health promotion interventions.

Association between objectively measured physical activity and body mass index with low back pain: a large-scale cross-sectional study of Japanese men.

BACKGROUND: The relationship between the combination of physical activity (PA) and body mass index (BMI) with low back pain (LBP) is unclear. The present study offers a cross-sectional assessment of how combinations of PA and BMI are related to LBP in Japanese men. METHODS: Participants were 4022 Japanese men (mean age = 47) who underwent regular clinical examinations. PA was measured using a uniaxial accelerometer and divided into tertiles (PAhigh, PAmiddle, PAlow). A self-administered questionnaire was used to report on persistent LBP experience, drinking and smoking habits, and any existing lifestyle diseases. After covariance adjustment, a logistic regression model was used to assess how combinations of PA and BMI are related to persistent LBP. RESULTS: 428 of the participants had persistent LBP. A clear negative dose-response relationship was found between PA levels and persistent LBP (P for linearity = 0.012). Regarding BMI, odd ratios were shown to be higher in the overweight/obese category (BMI ≥ 25 kg/m2) than for the normal weight category (BMI < 25 kg/m2). When the PAhigh was taken as the reference in the normal weight category, odds ratios for PAlow and PAmiddle in the normal weight category were shown to be high. Moreover, in the overweight/obese category, odd ratios for every fitness level were also high as for the normal weight category. CONCLUSION: The present study showed that both PA and BMI are related to persistent LBP. Also, the prevalence of persistent LBP became higher when PAlow and high BMI are combined rather than the group of PAhigh and low BMI combination.

The influence of a consumer-wearable activity tracker on sedentary time and prolonged sedentary bouts: secondary analysis of a randomized controlled trial.

OBJECTIVE: A recent meta-analysis surmised pedometers were a useful panacea to independently reduce sedentary time (ST). To further test and expand on this deduction, we analyzed the ability of a consumer-wearable activity tracker to reduce ST and prolonged sedentary bouts (PSB). We originally conducted a 12-month randomized control trial where 800 employees from 13 organizations were assigned to control, activity tracker, or one of two activity tracker plus incentive groups designed to increase step count. The primary outcome was accelerometer measured moderate-to-vigorous physical activity. RESULTS: We conducted a secondary analysis on accelerometer measured daily ST and PSB bouts. A general linear mixed model was used to examine changes in ST and prolonged sedentary bouts, followed by between-group pairwise comparisons. Regression analyses were conducted to examine the association of changes in step counts with ST and PSB. The changes in ST and PSB were not statistically significant and not different between the groups (P < 0.05). Increases in step counts were concomitantly associated with decreases in ST and PSB, regardless of intervention (P < 0.05). Caution should be taken when considering consumer-wearable activity trackers as a means to reduce sedentary behavior. Trial registration NCT01855776 Registered: August 8, 2012.

The Association of Fit-Fat Index with Incident Diabetes in Japanese Men: A Prospective Cohort Study.

Type 2 diabetes is increasing globally and in Asia. The purpose of this study was to examine the association of a fit-fat index (FFI) with diabetes incidence among Japanese men. In total 5,014 men aged 18-64 years old, who had an annual health check up with no history of major chronic disease at baseline from 2002 to 2009 were observed. CRF was estimated via cycle ergometry. Overall, 7.6% of the men developed diabetes. The mean follow-up period was 5.3 years. Hazard ratios, 95% confidence intervals and P trend for diabetes incidence were obtained using the Cox proportional hazards model while adjusting for confounding variables. High FFI demonstrated lower risk 0.54 (0.36-0.82) compared to low BMI 0.63 (0.44-0.90), low WHtR 0.64 (0.41-1.02), and High CRF 0.72 (0.51-1.03). FFI showed a marginally stronger dose response relationship across quartiles (P (trend) =0.001) compared to BMI (P (trend) =0.002), WHtR (P (trend) =0.055), and CRF (P (trend) =0.005). Overall, both fitness and fatness play independent roles in determining diabetes incidence in Japanese men. FFI may be a more advantageous physical fitness measure because it can account for changes in fitness and/or fatness.

Importance of Achieving a "Fit" Cardiorespiratory Fitness Level for Several Years on the Incidence of Type 2 Diabetes Mellitus: A Japanese Cohort Study.

BACKGROUND: The "Physical Activity Reference for Health Promotion 2013" provides "fit" reference values for cardiorespiratory fitness (CRF) for good health. The importance of achieving a fit CRF level for several years on the subsequent prevention of type 2 diabetes mellitus (T2DM) remains to be clarified. METHODS: This cohort study was conducted in 2,235 nondiabetic males aged 21 to 59 years, enrolled in April 1986 through March 1987. We calculated the ratio of the area under the curve (AUCratio) for actual measured values and the AUC for the reference values of CRF in each individual during an 8-year measurement period before the baseline. According to whether they met a fit CRF level or not, participants were categorized into groups based on the AUCratio (FitAUC or UnfitAUC) and initial CRF (Fitinitial or Unfitinitial), respectively. T2DM was evaluated on health checkups until March 2010. RESULTS: During the follow-up period, 400 men developed T2DM. After adjustment for confounders, as compared with those in the FitAUC group, the hazard ratio (HR) for those in the UnfitAUC group was 1.33 (95% confidence interval [CI], 1.06-1.65). A combined analysis with the categories of initial value and AUCratio showed that, compared with the Fitinitial and FitAUC group, the HRs of Fitinitial and UnfitAUC, Unfitinitial and FitAUC, and Unfitinitial and UnfitAUC groups were 1.41 (95% CI, 0.99-2.00), 1.18 (95% CI, 0.81-1.70), and 1.40 (95% CI, 1.08-1.83), respectively. CONCLUSION: Achievement of a fit CRF level established in the Japan physical activity guideline for several years was associated with lower subsequent risk of T2DM.