cardiovascular diseases

Whether physical activity attenuates the association of total daily sitting time with cardiovascular disease and diabetes incidence is unclear. This systematic review and meta-analysis examined the association of total daily sitting time with cardiovascular disease and diabetes with and without adjustment for physical activity.

EVIDENCE ACQUISITION:

PubMed, Web of Science, BASE, MEDLINE, Academic Search Elite, and ScienceDirect were searched for prospective studies, published between January 1, 1989, and February 15, 2019, examining the association of total daily sitting time with cardiovascular disease or diabetes outcomes. Data extraction and study quality assessments were conducted by 2 independent reviewers. Pooled hazard ratios (HRs) were calculated using a fixed-effects model. The quality assessment and meta-analysis procedures were completed in 2018.

EVIDENCE SYNTHESIS:

Nine studies with 448,285 participants were included. A higher total daily sitting time was associated with a significantly increased risk of cardiovascular disease (HR=1.29, 95% CI=1.27, 1.30, p<0.001) and diabetes (HR=1.13, 95% CI=1.04, 1.22, p<0.001) incidence when not adjusted for physical activity. The increased risk for diabetes was unaffected when adjusting for physical activity (HR=1.11, 95% CI=1.01, 1.19, p<0.001). For cardiovascular disease, the increased risk was attenuated but remained significant (HR=1.14, 95% CI=1.04, 1.23, p<0.001).

CONCLUSIONS:

Higher levels of total daily sitting time are associated with an increased risk of cardiovascular disease and diabetes, independent of physical activity. Reductions in total daily sitting may be recommended in public health guidelines.

Studies have shown bidirectional relationships between short- or long-sleep duration and risk for obesity, non-communicable diseases, all-cause mortality and cardiovascular disease mortality. Increasing sleep duration may be an appropriate strategy to reduce cardiometabolic riskin short-sleeping individuals. The aim is to review the effects of sleep extension interventions on cardiometabolic risk in adults. The PubMed and Scopus databases were searched for relevant, English, peer-reviewed scientific publications (until August 2018). Seven studies that aimed to increase sleep duration in adults by any sleep extension intervention and described at least one cardiometabolic risk factor were included. These studies had a combined sample size of 138 participants who were either healthy (n = 14), healthy short-sleeping (n = 92), overweight short-sleeping (n = 10), or pre- or hypertensive short-sleeping (n = 22) individuals. The durations of the sleep extensioninterventions ranged from 3 days to 6 weeks, and all successfully increased total sleep time by between 21 and 177 min. Sleep extensionwas associated with improved direct and indirect measures of insulin sensitivity, decreased leptin and peptide tyrosine-tyrosine, and reductions in overall appetite, desire for sweet and salty foods, intake of daily free sugar, and percentage of daily caloric intake from protein. This review provides preliminary evidence for a role for sleep extension to improve cardiometabolic outcomes and directive towards future studies in the field of cardiometabolic health and sleep.

IMPORTANCE:

Recent guidelines have recommended nonfasting for routine testing of lipid levels based on comparisons of nonfasting and fasting populations. However, no previous study has examined the association of cardiovascular outcomes with fasting vs nonfasting lipid levels measured in the same individuals.

OBJECTIVE:

To compare the association of nonfasting and fasting lipid levels with prospectively ascertained coronary and vascular outcomes and to evaluate whether a strategy of using nonfasting instead of fasting lipid level measurement would result in misclassification of risk for individuals undergoing evaluation for initiation of statin therapy.

DESIGN, SETTING, AND PARTICIPANTS:

This post hoc prospective follow-up of a randomized clinical trial included 8270 of 10 305 participants from the Anglo-Scandinavian Cardiac Outcomes Trial-Lipid Lowering Arm (ASCOT-LLA) with nonfasting and fasting lipid levels measured 4 weeks apart (including 6855 participants with no prior vascular disease) (median follow-up, 3.3 years; interquartile range, 2.8-3.6 years). Data were collected from February 1, 1998, to December 31, 2002, and analyzed from February 1, 2016, to November 30, 2018. Multivariable Cox models, adjusted for cardiovascular risk factors, were calculated for 40-mg/dL (1-mmol/L) higher values of nonfasting and fasting lipids.

MAIN OUTCOMES AND MEASURES:

The trial's primary end point consisted of major coronary events (nonfatal myocardial infarction [MI] and fatal coronary heart disease [212 events]). Secondary analyses examined atherosclerotic cardiovascular disease (ASCVD) events (including MI, stroke, and ASCVD death [351 events]).

RESULTS:

Among the 8270 participants (82.1% male; mean [SD] age, 63.4 [8.5] years), nonfasting samples had modestly higher triglyceride levels and similar cholesterol levels compared to fasting samples. Associations of nonfasting lipid levels with coronary events were similar to those for fasting lipid levels. For example, adjusted hazard ratios (HRs) per 40-mg/dL of low-density lipoprotein cholesterol were 1.32 (95% CI, 1.08-1.61; P = .007) for nonfasting levels and 1.28 (95% CI, 1.07-1.55; P = .008) for fasting levels. For the primary prevention group, adjusted HRs were 1.42 (95% CI, 1.13-1.78; P = .003) for nonfasting levels and 1.37 (95% CI, 1.11-1.69; P = .003) for fasting levels. Results were consistent by randomized treatment arm (atorvastatin calcium, 10 mg/d, or placebo) and similar for ASCVD events. Concordance of fasting and nonfasting lipid levels for classifying participants into appropriate ASCVD risk categories was high (94.8%).

CONCLUSIONS AND RELEVANCE:

Measurement of nonfasting and fasting lipid levels yields similar results in the same individuals for association with incident coronary and ASCVD events. These results suggest that routine measurement of nonfasting lipid levels may help facilitate ASCVD risk screening and treatment, including consideration of when to initiate statin therapy.

BACKGROUND:

Sedentary behavior is associated with health risks in adults. The potential benefits of reducing sedentary time may be dependent not only on decrease per se, but also on the type of activity it replaces. Few longitudinal studies have investigated the effects on mortality when replacing objectively assessed sedentary time with another physical activity (PA) behavior.

OBJECTIVE:

To investigate the effects of replacing objectively assessed sedentary time with time in light-intensity PA or moderate-vigorous PA (MVPA) on all-cause mortality, cardiovascular disease (CVD) mortality or cancer mortality in a cohort with 15 years follow-up time.

METHODS:

In total, 851 women and men from the population-based Sweden Attitude Behaviour and Change study were included. Time spent sedentary, in light-intensity PA and in MVPA were assessed using an Actigraph 7164 accelerometer. Mortality data were obtained from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of mortality with 95% confidence intervals (CI) and isotemporal substitution models were used to estimate the effect of replacing sedentary behavior with PA for the same amount of time.

RESULTS:

Over a follow-up of 14.2 years (SD 1.9) with 12,117 person-years at risk, 79 deaths occurred, 24 deaths from CVD, 27 from cancer, and 28 from other causes. Replacing 30 minutes/day of sedentary time with light-intensity PA was associated with significant reduction in all-cause mortality risk (HR: 0.89, 95% CI: 0.81-0.98) and CVD mortality risk (HR: 0.76, 95% CI: 0.63-0.92). Replacing 10 minutes of sedentary time with MVPA was associated with reduction in CVD mortality risk (HR: 0.62, 95% CI: 0.42-0.91). No statistically significant reductions were found for cancer mortality.

CONCLUSION:

This statistical modelling study suggests that replacing sedentary time with light-intensity PA could have beneficial effect on both all-cause mortality and CVD mortality. Replacing sedentary time with MVPA could reduce CVD mortality.