How do the authors make sense of these result, as participants are one year older at Time 2?
First, the attrition between Time 1 and Time 2 was substantial (40% of participants), and this is handled using list-wise deletion. That is, any one who did not complete both assessments was not included in the analyses. List-wise deletion can lead to serious bias in results. Analyses should be re-done using a more sophisticated method for handling missing data, such as multiple imputation or full-information maximum likelihood (Shafer & Graham, 2002, Psychological Methods).