<p class="MsoNormal" style="line-height: 200%;"><strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';">Background:</span></strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';"> Allostatic load (AL) is a model of cumulative physiological dysregulation from lifetime exposure to chronic stress that has been little studied in US Hispanics.&nbsp; To examine whether migration and duration of residence within and outside the US are associated with AL, we investigated AL accumulation patterns among age-, sex, and nativity subgroups in the Hispanic Community Health Study/ Study of Latinos. <strong></strong></span></p><p class="MsoNormal" style="line-height: 200%;"><strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';">Methods:</span></strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';"> We studied 15,830 Hispanic participants aged 18-74 years old, 77% of whom were born outside the US. We developed an index of AL based upon values from 16 physiological markers that spanned the cardiometabolic, parasympathetic, and inflammatory systems</span><span style="font-size: 11pt; line-height: 200%; font-family: Arial, sans-serif;">.</span><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';"> We computed mean standardized AL scores using log-linear models across age categories (18-39, 40-54, 55-74), stratified by sex and nativity status. Foreign-born participants were further stratified by years of residence in the US and age at migration using median value cut-points. <strong></strong></span></p><p class="MsoNormal" style="line-height: 200%;"><strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';">Results: </span></strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';">In persons younger than 55 years, after control for socioeconomic and behavioral factors, AL was highest among US born individuals, intermediate in foreign-born Hispanics with longer duration (≥10 years) in the US, and lowest among those with shorter duration in the US&nbsp; (&lt;10 years) (<em>P</em> &lt;0.0001 for increasing trend). Similarly, AL increased among the foreign-born with earlier age at immigration. These associations of AL with nativity and time since migration were not found among individuals aged 55 years or older.&nbsp; In specific groups including those of Dominican, Cuban, Mexican, and Puerto Rican background, a similar association was found between AL and nativity and duration of US residence. <strong></strong></span></p><p>&nbsp;</p><p class="MsoNormal" style="line-height: 200%;"><strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';">Conclusions: </span></strong><span style="font-size: 11.0pt; line-height: 200%; font-family: 'Arial','sans-serif';">Our findings support a "healthy immigrant" effect that is no longer apparent at older ages. More research is needed to understand risk and resilience factors that drive these nativity differences in age patterns of AL in Hispanics.&nbsp;</span></p>