Abstract
IMPORTANCE: While walking and similar physical activities provide numerous health benefits, particularly for aging inactive adults, many interventions are not accessible or relevant for all populations. Expanding the range of effective programs represents a critical goal. OBJECTIVE: To test whether counseling delivered by a customized, computer-driven short message service (SMS) system is comparable to standard human telephone counseling for increasing 12-month walking among inactive Hispanic or Latino/a adults. DESIGN, SETTING, AND PARTICIPANTS: This parallel-group randomized equivalence clinical trial enrolled adults from November 2015 to September 2017, with follow-up through October 2018. Data analysis was performed from January 2023 to December 2024. The evidence-derived equivalence margin was 30 minutes of walking per week. Participants were inactive adults ages 35 to 79 years of primarily Latin American descent from 5 northern California counties. INTERVENTIONS: Participants were randomized to receive a customized version of the evidence-supported Active Choices physical activity telephone advising program, delivered through trained human advisors or an interactive computerized SMS (text-messaging) system for 12 months. MAIN OUTCOMES AND MEASURES: The primary outcome was change in total volume of walking minutes per week at the end of the 12-month interventions using validated interview assessment corroborated with accelerometry. Intention-to-treat principles were used. RESULTS: Among 280 randomized participants (203 [72.5%] female; mean [SD] age, 51.2 (8.9) years), 139 were randomized to a human phone advisor and 141 were randomized to the SMS intervention. More than half of participants (145 participants [51.8%]) reported household income in the very low income range, and the mean (SD) body mass index was 33.1 (5.0). A total of 249 participants (88.9%) completed the study. At 12 months, mean (SD) walking increased 116.4 (2-sided 90% CI, 92.3 to 140.5) minutes per week (P < .001) for the human advisor cohort and 113.6 (2-sided 90% CI, 89.8 to 137.4) minutes per week (P < .001) for the SMS cohort (difference, 2.8 [90% CI, -23.8 to 29.4] minutes per week; P = .86). This finding supports equivalence. Benefits occurred in both groups for weight maintenance, sedentary behavior, and well-being outcomes, as well as additional physical activity types. CONCLUSIONS AND RELEVANCE: In this study of SMS vs human phone advising, a customizable SMS system produced significant 12-month walking increases for aging Latino/a adults comparable to the significant improvements attained by participants in the human advisors group. These results provide support for such mobile health platforms, which can expand program choices for broader segments of the population. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02385591.