Dyadic Associations of Physical Activity, Diet Quality, and Body Mass Index in Black Prostate Cancer Survivors and their Spouses: An Actor-Partner Interdependence Model Analysis.

BACKGROUND: Although prostate cancer (PCa) survivors' health is closely interrelated with that of their spouses/significant others (hereafter spouses), little is known about this interdependence among Black PCa survivors. This study examined the concordance of health behaviors (physical activity (PA), diet quality) and body mass index (BMI) within survivor-spouse dyads, and how each individual's PA and diet quality relate to the other's BMI. METHODS: Ninety-three Black PCa survivor-spouse dyads completed a survey on PA and diet quality. Height and weight were also self-reported and used to calculate BMI. We assessed PA, diet quality, and BMI concordance using intraclass correlation coefficients (ICCs). Actor and partner effects of PA and diet quality on BMI were tested via actor-partner interdependence models. RESULTS: The mean BMI of PCa survivors and spouses was 31.10 kg/m2 and 30.52 kg/m2, respectively. ICCs were 0.000 for PA (negligible), 0.453 for diet quality (high), and 0.093 for BMI (small-to-medium). A significant actor effect showed that higher PA among PCa survivors was associated with lower BMI (β = -0.236, p = 0.012). Meanwhile, no significant partner effects were observed. CONCLUSIONS: The high concordance in diet quality suggests that engaging spouses may be a promising strategy to improve Black PCa survivors' dietary behaviors. Enhancing Black survivors' PA remains critical for effective weight management. Future research should identify modifiable factors that affect spouses' BMI to inform the development of dyadic, weight-management interventions for Black PCa survivors and their spouses. Such efforts may help reduce the disproportionate survivorship burden among Black men.