Distance walked and run as improved metrics over time-based energy estimation in epidemiological studies and prevention; evidence from medication use

Content validity and test–retest reliability with principal component analysis of the translated Malay four-item version of Paffenbarger physical activity questionnaire

Purpose

This study aimed to develop the construct validity for the Malay version of the Paffenbarger physical activity questionnaire (PPAQ) by adapting the original questionnaire to suit the local context.

Design/methodology/approach

The PPAQ was adopted and translated into the Malay language and modified to reach good content agreement among a panel of experts. A total of 65 participants aged 22–55 years old, fluent and literate in the Malay language were selected. Principal component analysis (PCA) was used to investigate construct validity. Reliability of this adapted instrument was analyzed according to types of variables.

Findings

The panel of experts reached a consensus that the final four items chosen in the adapted Malay version of PPAQ were valid and supported by a good content validity index (CVI). In total, two domains consonant with the operational domain definition were identified by PCA. Based on scores from intensity and duration of exercise, the study further divided the group into who were physically active and those who chose the unstructured physical activity. Relative reliability after a 14-day interval demonstrated moderate strength of agreement with an acceptable range of measurement error.

Research limitations/implications

PPAQ has been used worldwide but was less familiar in the local context. The Malay-four item PPAQ will provide the locally validated version of physical activity questionnaire. In addition, the authors have improved the original PPAQ by dividing the question items into two distinct domains which will effectively identify those who are physically active and those who are involved in unplanned exercise. Nevertheless, further research is recommended in bigger and heterogeneous samples along with a number of reliability tests.

Practical implications

To the authors’ knowledge, this is the first study to assess internal structure of the four-item version of PPAQ. This analysis successfully identified two components with eigenvalue more than one in the Malay four-item PPAQ. Based on this, the authors were able to separate pool of population into two groups, which are physically active and unplanned exercise (involved in unstructured exercise). The ability of the validated questionnaire to divide the population into various intensities of physical activity is a novel one, which may be useful in many public health studies where high intensity of physical activity; hence, greater energy expenditure is associated with increased longevity, better health benefit and improved cognitive function.

Social implications

In addition, the second domain “unplanned exercise” was successfully grouped together. Implication of the unplanned exercise component is to identify pool of population with active lifestyle awareness and choose the unstructured exercise instead of vigorous and formal exercising. Even though the amount of intensity and duration of incidental exercise does not reach recommended public health recommendation, it has been proven that preferred healthier lifestyle is positively associated with better cognition in later life.

Originality/value

The adapted Malay version of PPAQ has sound psychometric properties and could assist in differentiating groups of population based on their physical activity.

Reduced risk of incident kidney cancer from walking and running

PURPOSE

This study aimed to test whether incident kidney cancer risk is associated with exercise energy expenditure (i.e., metabolic equivalents, 1 MET) when calculated from distance walked or run.

METHODS

Hazard ratios (HR) and 95% confidence intervals (95% CI) from Cox proportional hazard analyses of self-reported physician-diagnosed incident kidney cancer versus MET-hours per week in 91,820 subjects recruited between 1991 and 1993 (7.7 yr follow-up of 42,833 subjects) and between 1998 and 1999 (6.4 yr follow-up of 33,053 subjects) as part of the National Runners' Health Study and between 1998 and 1999 as part of the National Walkers' Health Study (5.7 yr follow-up of 15,934 subjects).

RESULTS

Fifty-two incident cancers were reported. Age- and sex-adjusted risk declined 1.9% per MET-hour per week run or walked (HR = 0.981, 95% CI = 0.964-0.997, P = 0.02). Compared with walking or running below guidelines levels (<7.5 MET·h·wk(-1)), the risk for incident kidney cancer was 61% lower for meeting the guidelines (HR = 0.39, 95% CI = 0.11-1.08, P = 0.07 for 7.5-12.5 MET·h·wk(-1)), 67% lower for exercising one to two times the recommended level (HR = 0.33; 95% CI = 0.15-0.72, P = 0.005 for 12.6-25.1 MET·h·wk(-1)), and 76.3% lower for exercising two times or more the recommended level (HR = 0.24, 95% CI = 0.11-0.52, P = 0.0005 for ≥ 25.2 MET·h·wk(-1)). Incident kidney cancer risk also increased in association with baseline body mass index (P = 0.002), smoking (P = 0.02), and hypertensive (P = 0.007) and diabetes medication use (P = 0.01); however, exercise-associated reductions in kidney cancer risk persisted for 12.6-25.1 MET·h·wk(-1) (HR = 0.35, P = 0.01) and ≥ 25.2 MET·h·wk(-1) (HR = 0.29, P = 0.004) vis-à-vis <7.5 MET·h·wk(-1) when also adjusted for body mass index, hypertension, diabetes, and pack-years smoked.

CONCLUSION

Running and walking may reduce incident kidney cancer risk independent of its other known risk factors.

An investigation and comparison of the effectiveness of different exercise programmes in improving glucose metabolism and pancreatic β cell function of type 2 diabetes patients

BACKGROUND

Moderately intensive aerobic exercise can improve glucose metabolism and pancreatic β cell function in diabetic patients. To date, there is no evidence to support the long-term effectiveness of home-based exercise interventions on these outcomes.

OBJECTIVE

This study investigated the effectiveness of two moderately intense exercise programmes on glucose metabolism and pancreatic β cell function in type 2 diabetes mellitus (T2DM) patients.

METHODS

A randomised controlled trial of 120 T2DM patients (with a mean age of 55.54 ± 9.09 years) was conducted. Patients were assigned by block randomisation to either an aerobic exercise group (AEG), an accumulated million steps group (AMSG), or a control group (CG); each consisting of 40 patients. Glucose metabolism and pancreatic β cell function of patients were measured at three time intervals for 1 year.

RESULTS

There was no difference in baseline scores, and respective compliance rates for the AEG and AMSG were 94.4% and 99.2%. After generalised estimating equation analysis, the AMSG results for glycated haemoglobin (HbA1c) were significantly lower than those of the CG. The insulinogenic index-acute insulin response (BIGTT-AIR ) of both exercise groups was significantly higher than that of the CG. The AMSG group improved their overall HbA1c and BIGTT-AIR results compared with the AEG group after 3 months exercise programme (T1 ) and 12 months of implementation (T2 ).

CONCLUSION

This study demonstrates that regardless of the type of exercise intervention, it is potentially beneficially effective for glucose metabolism and pancreatic β cell function in T2DM patients. The AMSG had better glucose metabolism and pancreatic β cell function compared with those in the AEG. Nurses can easily integrate exercise interventions into T2DM patient care plans.

Increased cardiovascular disease mortality associated with excessive exercise in heart attack survivors

OBJECTIVE

To test whether greater exercise is associated with progressively lower mortality after a cardiac event.

PATIENTS AND METHODS

We used Cox proportional hazard analyses to examine mortality vs estimated energy expended by running or walking measured as metabolic equivalents (3.5 mL O2/kg per min per day or metabolic equivalent of task-h/d [MET-h/d]) in 2377 self-identified heart attack survivors, where 1 MET-h/d is the energy equivalent of running 1 km/d. Mortality surveillance via the National Death Index included January 1991 through December 2008.

RESULTS

A total of 526 deaths occurred during an average prospective follow-up of 10.4 years, 376 (71.5%) of which were related to cardiovascular disease (CVD) (International Statistical Classification of Diseases, 10th Revision codes I00-I99). CVD-related mortality compared with the lowest exercise group decreased by 21% for 1.07 to 1.8 MET-h/d of running or walking (P=.11), 24% for 1.8 to 3.6 MET-h/d (P=.04), 50% for 3.6 to 5.4 MET-h/d (P=.001), and 63% for 5.4 to 7.2 MET-h/d (P<.001) but decreased only 12% for ≥7.2 MET-h/d (P=.68). These data represent a 15% average risk reduction per MET-h/d for CVD-related mortality through 7.2 MET-h/d (P<.001) and a 2.6-fold risk increase above 7.2 MET-h/d (P=.009). Relative to the risk reduction at 7.2 MET-h/d, the risk for ≥7.2 MET-h/d increased 3.2-fold (P=.006) for all ischemic heart disease (IHD)-related mortalities but was not significantly increased for non-IHD-CVD, arrhythmia-related CVD, or non-CVD-related mortalities.

CONCLUSION

Running or walking decreases CVD mortality risk progressively at most levels of exercise in patients after a cardiac event, but the benefit of exercise on CVD mortality and IHD deaths is attenuated at the highest levels of exercise (running: above 7.1 km/d or walking briskly: 10.7 km/d).

Dose-response relationship between exercise and respiratory disease mortality

PURPOSE

The objective of this study is to assess prospectively the dose-response relationship between respiratory disease (ICD10: J1-99), pneumonia (ICD10: J12.0-18.9), and aspiration pneumonia mortality (ICD10: J69) versus baseline walking and running energy expenditure (MET · h · d(-1), 1 MET = 3.5 mL O2 · kg(-1) · min(-1)).

METHODS

We conducted Cox proportional hazard analyses of 109,352 runners and 40,798 walkers adjusted for age, sex, smoking, diet, alcohol, and education.

RESULTS

There were 236 deaths with respiratory disease listed as the underlying cause, and 833 deaths were respiratory disease related (entity axis diagnosis). Included among these were 79 deaths with pneumonia listed as the underlying cause and 316 pneumonia-related deaths, and 77 deaths were due to aspiration pneumonia. There was no significant difference in the effect of running compared with walking (per MET-hour per day) on mortality; thus, runners and walkers were combined for analysis. Respiratory disease mortality decreased 7.9% per MET-hour per day as the underlying cause (95% CI, 1.6%-14.0%; P = 0.01) and 7.3% for all respiratory disease-related deaths (95% CI, 4.2%-10.4%; P = 10(-5)). Pneumonia mortality decreased 13.1% per MET-hour per day as the underlying cause (95% CI, 2.6%-23.2%; P = 0.01) and 10.5% per MET-hour per day for all pneumonia-related deaths (95% CI, 5.4%-15.5%; P = 0.0001). The risk for aspiration pneumonia mortality also did not differ between running and walking, and it decreased 19.9% per MET-hour per day run or walked (95% CI, 8.9%-30.2%; P = 0.0004). These results remained significant when additionally adjusted for body mass index.

CONCLUSIONS

Higher doses of running and walking were associated with lower risk of respiratory disease, pneumonia, and aspiration pneumonia mortality in a dose-dependent manner, and the effects of running and walking appear equivalent. These effects appear to be independent of the effects of exercise on cardiovascular disease.

Walking and running are associated with similar reductions in cataract risk

PURPOSE

Habitual running has been associated with reduced risk of cataract development in one prospective study. The purposes of the current analyses were to provide further evidence of this potentially important benefit of vigorous exercise and to test whether moderate exercise (e.g., walking) provides as significant and equivalent reduction in cataract risk as vigorous exercise (e.g., running).

METHODS

Cox proportional hazard analyses of self-reported, physician-diagnosed incident cataracts versus baseline energy expenditure (METs) in 32,610 runners and 14,917 walkers during a 6.2-yr follow-up. Results are reported as hazard ratios (HR), percent risk reductions (100 (HR - 1)), and 95% confidence intervals (95% CI).

RESULTS

Runners and walkers reported 733 and 1074 incident cataracts during follow-up, respectively. When adjusted for sex, race, age, education, smoking, and intakes of meat, fruit, and alcohol, lower cataract risk was significantly associated with both running (HR = 0.960 per MET·h·d, 95% CI 0.935-0.986) and walking (HR = 0.918 per MET·h·d, 95% CI = 0.881-0.956), with no significant difference in the risk reduction per MET-hours per day between running and walking or between men and women. Compared with running or walking at or below guideline levels (≤1.8 MET·h·d), incident cataract risk was significantly lower for running or walking 1.8-3.6 (16.4% lower, 95% CI = 6.4%-25.3%), 3.6-5.4 (19.0% lower, 95% CI = 5.6%-30.4%), 5.4-7.2 (26.2% lower, 95% CI = 11.2%-38.7%), 7.2-9.0 (34.1% lower, 95% CI = 10.0%-51.2%), and ≥9 MET·h·d (41.6% lower, 95% CI = 19.8%-57.4%).

CONCLUSION

Moderate (walking) and vigorous (running) exercise were both significantly associated with lower cataract risk and their effects similar. Cataract risk appears to decrease linearly with increasing exercise energy expenditure through 9 MET·h·d.

Breast cancer mortality vs. exercise and breast size in runners and walkers

Purpose

Identify predictors of breast cancer mortality in women who exercised below (<7.5 metabolic equivalent hours/week, MET-hours/wk), at (7.5 to 12.5 MET-hours/wk), or above (≥12.5 MET-hours/wk) recommended levels.

Methods

Cox proportional hazard analyses of baseline pre-diagnosis MET-hours/wk vs. breast cancer mortality adjusted for follow-up age, race, baseline menopause, and estrogen and oral contraceptive use in 79,124 women (32,872 walkers, 46,252 runners) from the National Walkers' and Runners' Health Studies.

Results

One-hundred eleven women (57 walkers, 54 runners) died from breast cancer during the 11-year follow-up. The decline in mortality in women who exercised ≥7.5 MET-hours/wk was not different for walking and running (P = 0.34), so running and walking energy expenditures were combined. The risk for breast cancer mortality was 41.5% lower for ≥7.5 vs. <7.5 MET-hours/wk (HR: 0.585, 95%CI: 0.382 to 0.924, P = 0.02), which persisted when adjusted for BMI (HR: 0.584, 95%CI: 0.368 to 0.956, P = 0.03). Other than age and menopause, baseline bra cup size was the strongest predictor of breast cancer mortality, i.e., 57.9% risk increase per cup size when adjusted for MET-hours/wk and the other covariates (HR: 1.579, 95%CI: 1.268 to 1.966, P<0.0001), and 70.4% greater when further adjusted for BMI (HR: 1.704, 95%CI: 1.344 to 2.156, P = 10⁻⁵). Breast cancer mortality was 4.0-fold greater (HR: 3.980, 95%CI: 1.894 to 9.412, P = 0.0001) for C-cup, and 4.7-fold greater (HR: 4.668, 95%CI: 1.963 to 11.980, P = 0.0004) for ≥D-cup vs. A-cup when adjusted for BMI and other covariates. Adjustment for cup size and BMI did not eliminate the association between breast cancer mortality and ≥7.5 MET-hour/wk walked or run (HR: 0.615, 95%CI: 0.389 to 1.004, P = 0.05).

Conclusion

Breast cancer mortality decreased in association with both meeting the exercise recommendations and smaller breast volume.

Inadequate exercise as a risk factor for sepsis mortality

Objective

Test whether inadequate exercise is related to sepsis mortality.

Research Design and Methods

Mortality surveillance of an epidemiological cohort of 155,484 National Walkers' and Runners' Health Study participants residing in the United States. Deaths were monitored for an average of 11.6-years using the National Death index through December 31, 2008. Cox proportional hazard analyses were used to compare sepsis mortality (ICD-10 A40-41) to inadequate exercise (<1.07 METh/d run or walked) as measured on their baseline questionnaires. Deaths occurring within one year of the baseline survey were excluded.

Results

Sepsis was the underlying cause in 54 deaths (sepsis_underlying) and a contributing cause in 184 deaths (sepsis_contributing), or 238 total sepsis-related deaths (sepsis_total). Inadequate exercise was associated with 2.24-fold increased risk for sepsis_underlying (95%CI: 1.21 to 4.07-fold, P = 0.01), 2.11-fold increased risk for sepsis_contributing (95%CI: 1.51- to 2.92-fold, P<10⁻⁴), and 2.13-fold increased risk for sepsis_total (95%CI: 1.59- to 2.84-fold, P<10⁻⁶) when adjusted for age, sex, race, and cohort. The risk increase did not differ significantly between runners and walkers, by sex, or by age. Sepsis_total risk was greater in diabetics (P = 10⁻⁵), cancer survivors (P = 0.0001), and heart attack survivors (P = 0.003) and increased with waist circumference (P = 0.0004). The sepsis_total risk associated with inadequate exercise persisted when further adjusted for diabetes, prior cancer, prior heart attack and waist circumference, and when excluding deaths with cancer, or cardiovascular, respiratory, or genitourinary disease as the underlying cause. Inadequate exercise also increased sepsis_total risk in 2163 baseline diabetics (4.78-fold, 95%CI: 2.1- to 13.8-fold, P = 0.0001) when adjusted, which was significantly greater (P = 0.03) than the adjusted risk increase in non-diabetics (1.80-fold, 95%CI: 1.30- to 2.46-fold, P = 0.0006).

Conclusion

Inadequate exercise is a risk factor for sepsis mortality, particular in diabetics.

Walking and running produce similar reductions in cause-specific disease mortality in hypertensives

To test prospectively in hypertensives whether moderate and vigorous exercise produces equivalent reductions in mortality, Cox-proportional hazard analyses were applied to energy expenditure (metabolic equivalents hours/d [METh/d]) in 6973 walkers and 3907 runners who used hypertensive medications at baseline. A total of 1121 died during 10.2-year follow-up: 695 cardiovascular disease (International Classification of Diseases, Tenth Revision [ICD10] I00-99; 465 underlying cause and 230 contributing cause), 124 cerebrovascular disease, 353 ischemic heart disease (ICD10 I20-25; 257 underlying and 96 contributing), 122 heart failure (ICD10 I50; 24 underlying and 98 contributing), and 260 dysrhythmias (ICD10 I46-49; 24 underlying and 236 contributing). Relative to <1.07 METh/d, running or walking 1.8 to 3.6 METh/d produced significantly lower all-cause (29% reduction; 95% confidence interval [CI], 17%-39%; P=0.0001), cardiovascular disease (34% reduction; 95% CI, 20%-46%; P=0.0001), cerebrovascular disease (55% reduction; 95% CI, 27%-73%; P=0.001), dysrhythmia (47% reduction; 95% CI, 27%-62%; P=0.0001), and heart failure mortality (51% reduction; 95% CI, 21%-70%; P=0.003), as did ≥ 3.6 METh/d with all-cause (22% reduction; 95% CI, 6%-35%; P=0.005), cardiovascular disease (36% reduction; 95% CI, 19%-50%; P=0.0002), cerebrovascular disease (47% reduction; 95% CI, 6%-71%; P=0.03), and dysrhythmia mortality (43% reduction; 95% CI, 16%-62%; P=0.004). Diabetes mellitus and chronic kidney disease mortality also decreased significantly with METh/d. All results remained significant when body mass index adjusted. Merely meeting guideline levels (1.07-1.8 METh/d) did not significantly reduced mortality. The dose-response was significantly nonlinear for all end points except diabetes mellitus, and cerebrovascular and chronic kidney disease. Results did not differ between running and walking. Thus, walking and running produce similar reductions in mortality in hypertensives.

Reduced incidence of cardiac arrhythmias in walkers and runners

Purpose

Walking is purported to reduce the risk of atrial fibrillation by 48%, whereas jogging is purported to increase its risk by 53%, suggesting a strong anti-arrhythmic benefit of walking over running. The purpose of these analyses is to compare incident self-reported physician-diagnosed cardiac arrhythmia to baseline energy expenditure (metabolic equivalent hours per day, METhr/d) from walking, running and other exercise.

Methods

Proportional hazards analysis of 14,734 walkers and 32,073 runners.

Results

There were 1,060 incident cardiac arrhythmias (412 walkers, 648 runners) during 6.2 years of follow-up. The risk for incident cardiac arrhythmias declined 4.4% per baseline METhr/d walked by the walkers, or running in the runners (P = 0.0001). Specifically, the risk declined 14.2% (hazard ratio: 0.858) for 1.8 to 3.6 METhr/d, 26.5% for 3.6 to 5.4 METhr/d, and 31.7% for ≥5.4 METhr/d, relative to <1.8 METhr/d. The risk reduction per METhr/d was significantly greater for walking than running (P<0.01), but only because walkers were at 34% greater risk than runners who fell below contemporary physical activity guideline recommendations; otherwise the walkers and runners had similar risks for cardiac arrhythmias. Cardiac arrhythmias were unrelated to walking and running intensity, and unrelated to marathon participation and performance.

Conclusions

The risk for cardiac arrhythmias was similar in walkers and runners who expended comparable METhr/d during structured exercise. We found no significant risk increase for self-reported cardiac arrhythmias associated with running distance, exercise intensity, or marathon participation. Rhythm abnormalities were based on self-report, precluding definitive categorization of the nature of the rhythm disturbance. However, even if the runners’ arrhythmias include sinus bradycardia due to running itself, there was no increase in arrhythmias with greater running distance.

Walking versus running for hypertension, cholesterol, and diabetes mellitus risk reduction

OBJECTIVE

To test whether equivalent energy expenditure by moderate-intensity (eg, walking) and vigorous-intensity exercise (eg, running) provides equivalent health benefits.

APPROACH AND RESULTS

We used the National Runners' (n=33 060) and Walkers' (n=15 945) Health Study cohorts to examine the effect of differences in exercise mode and thereby exercise intensity on coronary heart disease (CHD) risk factors. Baseline expenditure (metabolic equivant hours per day [METh/d]) was compared with self-reported, physician-diagnosed incident hypertension, hypercholesterolemia, diabetes mellitus, and CHD during 6.2 years follow-up. Running significantly decreased the risks for incident hypertension by 4.2% (P<10(-7)), hypercholesterolemia by 4.3% (P<10(-14)), diabetes mellitus by 12.1% (P<10(-5)), and CHD by 4.5% per METh/d (P=0.05). The corresponding reductions for walking were 7.2% (P<10(-6)), 7.0% (P<10(-8)), 12.3% (P<10(-4)), and 9.3% (P=0.01). Relative to <1.8 METh/d, the risk reductions for 1.8 to 3.6, 3.6 to 5.4, 5.4 to 7.2, and ≥7.2 METh/d were as follows: (1) 10.1%, 17.7%, 25.1%, and 34.9% from running and 14.0%, 23.8%, 21.8%, and 38.3% from walking for hypercholesterolemia; (2) 19.7%, 19.4%, 26.8%, and 39.8% from running and 14.7%, 19.1%, 23.6%, and 13.3% from walking for hypertension; and (3) 43.5%, 44.1%, 47.7%, and 68.2% from running, and 34.1%, 44.2% and 23.6% from walking for diabetes mellitus (walking >5.4 METh/d excluded for too few cases). The risk reductions were not significantly different for running than walking for diabetes mellitus (P=0.94), hypertension (P=0.06), or CHD (P=0.26), and only marginally greater for walking than running for hypercholesterolemia (P=0.04).

CONCLUSIONS

Equivalent energy expenditures by moderate (walking) and vigorous (running) exercise produced similar risk reductions for hypertension, hypercholesterolemia, diabetes mellitus, and possibly CHD.