Supplemental income program design: A cluster-randomized controlled trial to examine the health and wellbeing effects on older adults by gender, duration, and payment frequency

Background: We documented results from a cluster-randomized controlled trial we designed to supplement in-comes in poor towns among adults 70 or older. We analyzed effects on health by gender, persistence over time, and variation by payment frequency. Methods: We compared supplemental income effects over an 18-month period for two towns in Yucatan, Mexico: Valladolid, where eligible individuals received a monthly income supplement over the entire analysis period, and Motul, a demographically matched control town, where eligible individuals received a bimonthly income supplement over the last 12 months of the analysis period. While differing in frequency of payment, supplements provided similar levels of income. We conducted three surveys of recipients: (1) at baseline, (2) six months after baseline, and (3) 18 months after baseline. Results: The primary outcomes we examined were peak expiratory flow, hemoglobin level, and verbal recall. The secondary outcomes were health care use and food availability. We found health benefits persisted for at least eighteen months for the monthly income supplement, with both males and females benefiting. Bimonthly income supplements had smaller health benefits. Conclusions: Older people in the developing world who lack social security benefits and health care may benefit most from monthly income programs. The greater payment frequency of monthly programs may influence how household resources are allocated. Supplemental income programs are common in low- and middle-income countries; hence, our results have implications for program design in many nations.