Accelerometer-determined physical activity volume and pattern with incident diabetes: prospective analyses of The Maastricht Study

Background: Physical activity (PA) is associated with reduced risk of type 2 diabetes mellitus (T2DM). Existing research focuses on associations with average weekly PA time or volume, which ignores potential importance of the varying patterns in which PA is accumulated.

Purpose: To examine associations of accelerometer-determined PA volume and pattern with incident T2DM

Methods: Participants (n=4526, 40-75y, without preexisting T2DM) from The Maastricht Study and wore an activPAL accelerometer (> 5 days). Prospective associations of stepping volume (steps/day) with incident T2DM were assessed using Cox proportional hazards models with restricted cubic splines, adjusted for age, sex, education, smoking and diet. Four indicators of variation in between- and within-day stepping pattern were modelled alongside total steps/day. These were: proportion of steps accumulated on the 2 most active days (%Active-2days), between-day (BDV) and within-day steps/day variability (WDV), and inter-daily step count stability (IS: the extent that daily stepping patterns are uniform).

Results: Over 34,130 person-years of follow-up (median 7.2y), 178 incident cases of T2DM were recorded. Average steps/day was associated with T2DM risk, (non-linearly, with steeper risk reduction earlier in the steps/day distribution). Compared to steps/day quintile one (lowest steps/day. Q1), adjusted HR were; Q2 0.70 (95%CI 0.46, 1.00), Q3 0.57 (0.37, 0.88), Q4 0.32 (0.19, 0.54), Q5 (highest steps/day) 0.41 (0.26, 0.67) (Ptrend <0.001). PA pattern metrics were associated with T2DM risk independently of PA volume. HRs for 10% increases in %Active-2days and IS were 0.72 (0.54, 0.97 p=0.02) and 1.83 (1.21, 3.02. p=0.002) respectively. Higher BDV but not WDV was also associated with lower T2DM risk.

Conclusions: Greater variability in PA accumulation was associated with lower diabetes risk, independent of PA volume.

Implications: Not all steps are equal. Alongside a higher overall volume, weekly PA patterns that are variable with some high ‘daily doses’ can additionally reduce T2DM risk.