Impact of traditional Chinese medicine on age trajectories of health: Evidence from the Taiwan Longitudinal Study on Aging

Although traditional Chinese medicine (TCM) is widely used, its effect on health outcomes is not well understood. This study employed a cohort sequential design to investigate levels and rates of change in health from midlife to older adulthood in TCM users and nonusers. A sample of 1,302 community-dwelling adults aged 53 to 80 was selected from individuals interviewed in the 1999 Taiwan Longitudinal Study on Aging (TLSA) and reinterviewed in 2003 and 2007. TCM users were identified as participants who reported visiting a Chinese medicine clinic in the year before each of the three interviews. Health outcomes included physical function, self-rated health, cognitive function, and depressive symptoms. Approximately one in five adults reported that they used TCM in at least one wave of the 3 interview years, but less than one in twenty across all waves. Controlling for time-varying sociodemographic and health conditions, levels and rates of change in physical and cognitive function did not differ according to TCM use. Although adults who reported using TCM had higher depressive symptoms (β_TCM = 0.979, 95% confidence interval (CI) = 0.200-1.758) and poorer self-rated health (β_TCM = -0.267, 95% CI = -0.267 to -0.081) at baseline, their rates of change in these outcomes did not differ from those who did not use TCM. Subgroup analyses revealed that TCM use benefited adults with higher depressive symptoms by attenuating worsening depressive symptoms (β_TCM×Age = -0.221, 95% CI = -0.434 to -0.007). Further research aimed at understanding the specific mechanisms by which TCM affects health outcomes is warranted.