Examining the Dose-Response Relationship between Physical Activity and Health Outcomes

Longitudinal description and prediction of physical inactivity among patients with borderline personality disorder and personality-disordered comparison subjects

BACKGROUND

The physical and psychological benefits of physical activity are well-known, and physical activity has been proven to be a helpful adjunct to psychotherapeutic treatment for many symptomatic disorders, including mood and anxiety disorders. The current study explores physical inactivity levels in patients with borderline personality disorder (BPD). The first aim of this study is to describe the 12-year course of physical inactivity in patients with BPD. The second aim is to examine predictors of physical inactivity, including adversity experiences, comorbid symptomatic (formerly axis I) disorders, medical disorders, and demographic factors.

METHODS

Two hundred and forty-five patients with BPD were interviewed seven times over 12-years of prospective follow-up as part of the McLean Study of Adult Development (MSAD). Patients were categorized as ever-recovered (i.e., patient had experienced a symptomatic and psychosocial recovery from BPD) or never-recovered. At each follow-up, patients reported physical activity levels (minutes of exercise per week) via a semi-structured interview- the Medical History and Services Utilization Interview (MHSUI). Data was collected from June 1992 to December 2018.

RESULTS

Never-recovered patients with BPD were significantly more inactive than their ever-recovered counterparts (p < 0.001). These rates of inactivity remained stable over time for both groups. Two significant multivariate predictors of inactivity were found: obesity (p = 0.003) and PTSD (p < 0.001).

CONCLUSIONS

Non-recovered BPD patients are more likely to be inactive than patients who have recovered. Both clinical and medical factors appear to contribute to inactivity levels in patients with BPD.

Association between physical activity and clinical outcomes in high-risk hypertension: Post-hoc analysis of SPRINT

Objective

Engaging in physical activity (PA) is recommended to reduce the risk of morbidity and mortality in patients with hypertension. However, the association between PA and clinical outcomes in individuals with high-risk hypertension is understudied. We examined the relationship between PA and clinical outcomes in the Systolic Blood Pressure Intervention Trial (SPRINT). SPRINT investigated the benefit of intensive (vs. standard) blood pressure treatment in patients with high-risk hypertension.

Methods

Baseline data on PA was self-reported. Vigorous-intensity PA (VPA) was categorized into 2 groups based on frequency of "Rarely or Never" and 1 or more sessions/month. Moderate-intensity PA (MPA) was also categorized into 2 groups based on average duration/day of <15 min and 15 or more minutes. Using multivariable Cox regression, we estimated the associations between PA the primary outcome which was a composite of cardiovascular events, and all-cause mortality.

Results

A total of 8,320 (age 67.8 ± 9.3, 34.9% women) of SPRINT participants with data on PA were included. During a median follow-up of 3.8 years, 619 primary outcome, and 419 all-cause mortality events occurred. Compared to not engaging in VPA, the risk of the primary outcome, myocardial infarction, and all-cause mortality (HR 95% CIs) associated with VPA of ≥1sessions/month was 0.79(0.65-0.94; p=0.009), 0.70(0.52-0.93; p=0.014) and 0.75(0.60-0.94; p=0.011), respectively. Similarly, the risk of the primary outcome and all-cause mortality (HR 95% CI) associated with engaging in MPA for ≥15 min/day, relative to <15 min/day was 0.76(0.63-0.93; p=0.008) and 0.80(0.62-1.02; p=0.066), respectively.

Conclusion

Among individuals with hypertension from the SPRINT study, VPA and MPA at a threshold of ≥1sessions/month and MPA of ≥15 min/day respectively, were both associated with a lower risk for cardiovascular events, and VPA was also associated with a reduced risk for all-cause mortality. Further studies are required to identify the optimal volume and intensity of PA in high-risk hypertension.

Fitness Trackers to Guide Advice on Activity Prescription

This Viewpoint discusses whether older self-report questionnaire studies and newer studies of fitness-tracking devices reach different conclusions about the dose of physical activity needed for health.

Relationship of Daily Step Counts to All-Cause Mortality and Cardiovascular Events

BACKGROUND

The minimal and optimal daily step counts for health improvements remain unclear.

OBJECTIVES

A meta-analysis was performed to quantify dose-response associations of objectively measured step count metrics in the general population.

METHODS

Electronic databases were searched from inception to October 2022. Primary outcomes included all-cause mortality and incident cardiovascular disease (CVD). Study results were analyzed using generalized least squares and random-effects models.

RESULTS

In total, 111,309 individuals from 12 studies were included. Significant risk reductions were observed at 2,517 steps/d for all-cause mortality (adjusted HR [aHR]: 0.92; 95% CI: 0.84-0.999) and 2,735 steps/d for incident CVD (aHR: 0.89; 95% CI: 0.79-0.999) compared with 2,000 steps/d (reference). Additional steps resulted in nonlinear risk reductions of all-cause mortality and incident CVD with an optimal dose at 8,763 (aHR: 0.40; 95% CI: 0.38-0.43) and 7,126 steps/d (aHR: 0.49; 95% CI: 0.45-0.55), respectively. Increments from a low to an intermediate or a high cadence were independently associated with risk reductions of all-cause mortality. Sex did not influence the dose-response associations, but after stratification for assessment device and wear location, pronounced risk reductions were observed for hip-worn accelerometers compared with pedometers and wrist-worn accelerometers.

CONCLUSIONS

As few as about 2,600 and about 2,800 steps/d yield significant mortality and CVD benefits, with progressive risk reductions up to about 8,800 and about 7,200 steps/d, respectively. Additional mortality benefits were found at a moderate to high vs a low step cadence. These findings can extend contemporary physical activity prescriptions given the easy-to-understand concept of step count. (Dose-Response Relationship Between Daily Step Count and Health Outcomes: A Systematic Review and Meta-Analyses; CRD42021244747).