Both low cardiorespiratory fitness and low serum vitamin D levels are associated with increased cardiovascular and all-cause mortality, but whether low vitamin D is independently associated with cardiorespiratory fitness in healthy adults is not known. We examined vitamin D levels and fitness in 200 healthy adults, participating in a double-blind clinical trial investigating statins and muscle performance (the STOMP study). Maximal aerobic exercise capacity (VO2max) was measured using metabolic gas analysis during graded treadmill exercise to exhaustion. Vitamin D [25(OH)D] was measured using enzyme-linked immunosorbent assay (ELISA). Daily physical activity was assessed using the Paffenbarger Physical Activity Questionnaire. Serum 25(OH)D concentration was positively related to VO2max (r =0.29, p=0.0001), even after adjusting for relevant predictors (e.g., age, gender and body mass index) (p= 0.0004). There was also a significant interaction between 25(OH)D level and self-reported hours of moderate to vigorous physical activity (MVPA) (p<0.02). With each standard deviation increase in vitamin D, VO2max increased by 2.6 ml/kg/min (p=0.0001) when MVPA was low (16 hr/wk), 1.6 ml/kg/min (p=0.0004) when MVPA was moderate (35 hr/wk), but only 0.07 ml/kg/min (p=0.9) when MVPA was high (64 hr/wk). In conclusion, serum vitamin D levels predict VO2max in adults; the effect is greatest among those with low levels of physical activity.

In a cohort of healthy adult athletes and sedentary controls, there was no association between physical activity measured by VO2 max and peripheral blood lymphocyte and granulocyte telomere length.

Background. In selected patients, stress-only SPECT imaging has been proposed as an alternative to rest-stress SPECT imaging to improve laboratory efficiency and reduce radiation exposure. The impact of attenuation correction (AC) upon interpretation, post-test patient management and cardiac risk stratification in relation to stress-only imaging is not well understood.Objectives. The purpose of this study was to determine the clinical value for laboratory throughput and predicting outcomes of normal and abnormal stress-only SPECT imaging with AC in a consecutive series of clinically referred patients.Methods. A retrospective analysis of 1,383 consecutive patients who were scheduled for stress-only SPECT imaging for symptom assessment of suspected myocardial ischemia was performed. All images had been interpreted and categorized using the standard 17-segment model without AC followed by AC. Follow-up data for 2.1 ± 1.3 years after SPECT imaging for the occurrence of cardiac events (non-fatal MI, cardiac death, and cardiac revascularization) previously collected by routine methods were reviewed.Results. Non-AC SPECT image interpretation revealed that 58% (802/1383) of patients had abnormal stress images. AC image interpretation of the abnormal non-AC images re-classified 83% (666/802) of these as normal. Among patients with abnormal stress images after AC (136/ 1383), 63% (86/136) returned for additional rest scans, while the remaining 37% (50/136) were clinically managed without further rest images. The incidence of cardiac death or non-fatal MI was very low in patients with normal stress-only scans (0.7%).Conclusion. A strategy of stress-only imaging with AC in symptomatic patients is an efficient method which appropriately identifies at risk and low-risk patients yielding a low percentage requiring rest imaging. Clinical decisions can be made based on abnormal stress-only imaging without further rest imaging if clinically appropriate. (J Nucl Cardiol 2013;20:27-37.)

In very elderly patients (≥80 years) with suspected CAD, SPECT MPI has prognostic and incremental value in the noninvasive cardiovascular assessment for risk stratification and may influence medical decisions.