Purpose
Applying the life course principles of linked lives (i.e., interpersonal influences) and timing of event (i.e., differential effects of an event resulting from different timing in a life course), this study explored 1) the concordance of physical activity (PA) trajectories between husbands and wives and 2) their relationships with physical limitations resulting from life-threatening diseases (LTDs) using the Panel Study of Income Dynamics.
Methods
In this study, PA trajectories, which represent the change in PA over time, included stable active (SA), activity adopters (AA), activity relapsers (AR), and stable sedentary (SS), developed from the transitional shift patterns (Levy & Cardinal, 2006), over three time points with two-year intervals. Participants were husbands of households who had remained in the same marriage between the year 1999 and 2003 in the United States (N=2,842; Mage=45.26, SDage=13.17). 1) Husbands' report of wives' PA trajectories (i.e., test of couple's longitudinal concordance), 2) quadratic terms of limitations resulting from LTDs for husbands and for wives (i.e., test of curvilinear relationship), and 3) the interaction between age and the quadratic term of limitations resulting from LTDs for husbands (i.e., test of the principle of timing of event) were hypothesized to predict husbands' PA trajectories. A Latent Class Growth Analysis (LCGA) was used to extract the PA trajectories and to examine the hypotheses.
Analysis/Results
Results of the multinomial regression, as a part of the LCGA that predicted husbands' trajectories, showed that wives' PA trajectories were related to husbands' PA trajectories (Odds Ratios [OR] ranged from 2.68 to 17.50, ps<.001). Wives' limitations resulting from LTDs were not associated with husbands' PA trajectories, while a significant interaction between age and the quadratic term of husbands' limitations resulting from LTDs was associated with the husbands' PA trajectories of SA (with AR as the reference group), OR=1.41, p<.05.
Conclusions
Generally, people diagnosed with LTDs with no resulting limitation showed an increased likelihood to be in SA rather than AR for vigorous PA. However, the protective effect declined and became negative with increased limitations resulting from LTDs. Additionally, this curvilinear pattern was moderated by age, for which younger individuals were more strongly associated with both positive and negative effects of limitations resulting from LTDs compared with older adults. Findings suggested that couples and families can be viable intervening units for PA promotion, and that strategies should be tailored to meet the needs of people at different ages during the experience of LTDs.