Measuring Nutrition Literacy in Breast Cancer Patients: Development of a Novel Instrument.

No nutrition literacy instruments have been tested in breast cancer survivors, yet nutrition is a critical lifestyle factor for optimizing weight and improving quality of life in breast cancer survival. Our objectives were to adapt our Nutrition Literacy Assessment Instrument for breast cancer populations and to pilot test its validity and reliability. We modified the instrument based on review by content experts in cancer and nutrition and cognitive interviews with 18 cancer survivors. The modified instrument (Nutrition Literacy Assessment Instrument for Breast Cancer, NLit-BCa) was pilot-tested with 17 high-risk women and 55 breast cancer survivors. We conducted the NLit-BCa on two separate occasions 4 weeks apart and assessed reliability by confirmatory factor analysis. Construct validity was evaluated by comparing results of the NLit-BCa to a Healthy Eating Index score derived from two separate 24-h dietary recalls. Content validity of the NLit-BCa was acceptable (0.93). Entire reliability for three instrument domains was substantial (>0.80), while remaining domains demonstrated fair or moderate reliability. Significant relationships were found between five of the six domains of nutrition literacy and diet quality (P < 0.05). The NLit-BCa is content valid and demonstrates promising reliability and construct validity related to diet quality, through a larger sample size, and removal of non-discriminating items is needed to confirm these findings. Thus, the NLit-BCa demonstrates potential for comprehensively measuring nutrition literacy in breast cancer populations.