Time-Series Analysis of Continuously Monitored Blood Glucose: The Impacts of Geographic and Daily Lifestyle Factors

Table 1

Explanatory variables.

Variable name	Description	Value/units in given time period^a
Calories consumed	From food and beverages	Total calories
Meds taken	Of any type	0 = no, 1 = yes
Insulin taken	Variety of slow, medium, and fast acting insulin medications	0 = no, 1 = yes
Movement intensity	Vector magnitude, square root of the sum of the squared 3-axis acceleration readings	Average vector magnitude^b
Exercise time	Aerobic, weights, walking, and so forth	Total minutes
Trip time	Time spent travelling by any mode	Total minutes
Automobile time	Time spent travelling by personal automobile	Total minutes
Public transit time	Time spent travelling by public transit (bus, streetcar, subway, and train)	Total minutes
At-home time	Time spent at home	Total minutes
Work/school time	Time spent at work or school	Total minutes
Shopping time	Time spent shopping (grocery, clothing, etc.)	Total minutes
Restaurants time	Time spent in a restaurant of any type	Total minutes
Out-of-home time	Time spent outside the home	Total minutes
Time spent with others	Time spent with other people involved	Total minutes
Time of day	Daytime (7:00AM to 7:00PM) or nighttime	0 = daytime, 1 = nighttime
Distance home	Straight-line distance between current location and home location	Average distance in kilometers

Time periods included the past 12 hours for aggregate correlation/regression analysis and over past 5 minutes for time series ARIMA modeling.
^bLow values are typically associated with stationary activities and higher values are indicative of more physically active periods.