Sedentary behaviour, physical activity, and risk of coronary artery disease and diabetes mellitus

Public examination of a doctoral dissertation in the field of Internal Medicine

Doctoral candidate: B.M. Ville Vasankari

Date and venue: 23.11.2018 at 12 noon, Kuopio University Hospital, Auditorium 2

Language of the public examination: Finnish

Language of the dissertation: English

Cardiovascular diseases (CVD), such as coronary artery disease (CAD), are a group of common diseases affecting the patient’s circulation system with a poor prognosis. CVDs are responsible for one third of all global deaths. In addition to mortality, CVDs often evoke serious symptoms, working disability and a reduced quality of life. In addition to genetic factors, the most important risk factors for CVDs, especially for CAD development, are hypercholesterolemia, hypertension, smoking and diabetes mellitus (DM). Furthermore, low physical activity (PA) is also considered as potential risk factor for CAD.

Sedentary behaviour (SB), defined as the time spent either sitting or lying, has recently been recognized as a risk factor for both CAD and DM. Corresponding, inadequate PA is considered as a major risk factor of CAD, DM and CVD mortality. Therefore, PA, which comprises activities consuming more energy than SB and standing, is a clinically relevant target of CAD prevention. Despite the contribution of SB and PA to the CAD burden, there are only few tools applied to increase PA along with a reduction of SB in CAD patients.

The present thesis is based on a large population-based sample (n=1398) of the Health 2011 study involving 18-85 -year-old Finnish adults. The main objective was to assess specific associations between parameters of SB and PA obtained by a novel accelerometer (Hookie AM 20 – Traxmeet Ltd.), and the risk factors for the development of CVDs. Furthermore, the differences in SB and PA among patients with CAD or DM and their non-CVD peers were investigated.

The associations of accelerometer-derived SB and PA profiles with an individual’s CVD risk were examined in this thesis. A higher number of daily SB bouts lasting >10 min was associated with an increased CVD risk (p=0.004). With respect to PA, the mean daily and weekly estimated energy consumption profiles in metabolic equivalents (MET) displayed the most significant association with lower CVD risk (p<0.001).

The differences in accelerometer-derived SB and PA were also compared between CAD patients and their non-CVD peers with different CVD risk profiles. There were no differences in SB and PA profiles between the CAD patients and high CVD risk persons. The number of >3 min moderate-to-vigorous PA bouts was on average 73 % higher among the low risk peers when compared to those subjects with CAD or a high CVD risk (p<0.001).

In addition, the relationships between SB and PA profiles, and prevalence of DM were investigated. In the multivariable analysis, the accumulated total time from <5 min standing bouts was observed to reduce the odds for diabetes (OR = 0.89).

In conclusion, both patient’s SB and PA should be considered in the preventive lifestyle therapy of CAD patients and their high CVD risk peers. DM patients should be encouraged to substitute prolonged sitting with periods of standing. In addition, novel tools should be devised to make PA guidance more effective in the rehabilitation of CAD patients.

The doctoral dissertation of Ville Vasankari, Bachelor of Medicine, entitled Sedentary behaviour, physical activity, and risk of coronary artery disease and diabetes mellitus will be examined at the Faculty of Health Sciences. The Opponent in the public examination will be Docent Mikko Pietilä of Turku University Central Hospital, and the Custos will be Professor Juha Hartikainen of the University of Eastern Finland.

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