Table 8.

Coefficients [s.e.] for the linear null models for percentage weight change. Every row corresponds to a model for weight change of individuals with an engagement time of 180 days and at least one friend, after correcting for self-selection bias. In these null models, the individuals have been reshuffled to different locations in the network, but preserving their personal features. The dataset used for this analysis is Group 1, where the total number of observations is 22 419 (842 uncensored), except for models that include as variable the average weight change of a user's friends (822 uncensored observations). We denote as uncensored observations those for whom we have the values of all variables and as censored observations those for whom we are missing the values of some variables. Superscript n.s. denotes not significant.

intercept	initial BMI	number of weigh-ins	time in the system	online communic.	k-shell index	number of friends	betweenness	inv. Mills ratio	adj. R2 (%)
3.85* [1.91]	−0.13*** [0.03]	−0.08*** [0.01]	−0.009*** [0.001]	−0.005*** [0.001]				−0.35n.s. [0.63]	24.1
0.34n.s. [1.89]	−0.13*** [0.03]	−0.09*** [0.01]	−0.009*** [0.002]		0.004n.s. [0.080]			1.39* [0.58]	20.7
0.39n.s. [1.88]	−0.14*** [0.03]	−0.09*** [0.01]	−0.009*** [0.002]			−0.004n.s. [0.005]		1.40* [0.57]	20.8
0.38n.s. [1.88]	−0.14*** [0.03]	−0.09*** [0.01]	−0.010*** [0.001]				11.31n.s. [13.57]	1.40*** [0.58]	20.8

***p < 0.001.

**p < 0.01.

*p < 0.05.