Dairy Consumption: Does It Make an Impact on Self-Reported Disease Activity of Inflammatory Arthritis?

Abstract

Background As researchers and the public become more cognizant of the impacts of diet and nutrition on health, continued research is needed to provide evidence to support dietary claims. At present, there exists mixed reporting on the effects of dairy consumption and disease activity of inflammatory arthritis (IA). Objective This study attempts to advance current research on the relationship between dairy consumption and self-reported disease activity in patients with IA and to investigate whether dietary modifications can be helpful as a conservative, cost-effective, and accessible supplement to established treatments. Methods Participants completed a modified diet history questionnaire (DHQ), which assessed dairy consumption over the past year, and a Routine Assessment of Patient Index Data 3 (RAPID3) questionnaire, which assessed a participants' self-reported inflammatory disease activity. DHQ and RAPID3 were analyzed using a Pearson product-moment partial correlation to assess variables' relationships. Participants completed the questionnaire in the setting of a rheumatology clinic. Two hundred and four participants were recruited for this study. All of the participants were at least 18 years of age, capable of giving informed consent, and were formally diagnosed with either rheumatoid arthritis or psoriatic arthritis by a board-certified rheumatologist. Results The results from the questionnaires found that dairy consumption does not contribute to self-reported IA disease activity. While 11 of the 16 DHQ variables maintained a positive correlation with the overall RAPID3 scores, none of these possessed statistical significance. Only when controlling for age and sex did the study find two statistically significant variable correlations between the quantity of milk consumed as a beverage (r=0.147, n=193, p=0.043) and milk added to cereal (r=0.170, n=189, p=0.019) with the RAPID3 scores. Conclusion In summation, the study found no notable correlation between dairy consumption and patients' self-reported IA disease activity.

Keywords: diet therapy; inflammatory arthritis; joint diseases; psoriatic arthritis; rheumatoid arthriitis.

Figure 1. RAPID3 self-reported disease activity vs. sex

Females had a statistically significant higher average self-reported overall disease activity of IA (10.8459 ±6.46494) as measured by the RAPID3 questionnaire compared to males (6.7282 ± 5.7893). RAPID3 - Routine Assessment of Patient Index Data 3 IA - inflammatory arthritis

Figure 2. Quantity of milk consumed as a beverage vs. overall RAPID3 score

A statistically significant positive correlation was found between the quantity of milk consumed as a beverage and the overall self-reported disease activity measured by the RAPID3 score. The average drinks consumed was (4.35 ± 4.12 fl oz/year) and the overall RAPID3 score (10.04 ± 6.57) whilst controlling for age (58.5 ± 14.6 years) and sex (77% female). This statistically significant positive correlation was only observed after controlling for age and sex. RAPID3 - Routine Assessment of Patient Index Data 3

Figure 3. Modified diet history questionnaire: assessed patient's dairy intake within the last 12 months (page 1)

Figure 4. Modified diet history questionnaire (pages 2 and 3)

Figure 5. Modified diet history questionnaire (pages 4 and 5)

Figure 6. Routine assessment of patient index data 3 (RAPID3) questionnaire that measures patient's self-reported disease activity of inflammatory arthritis