Intergenerational changes in knee height among Maya mothers and their adult daughters from Merida, Mexico

Objectives To analyze differences in knee height (KH) between adult Maya mothers and daughters in the city of Merida, Mexico, and determine if these differences are associated to their childhood socioeconomic conditions. Methods From September 2011 to January 2014, we measured KH and collected data on childhood conditions (place of birth, type of drinking water, family size [FS] and fathers’ occupation) from a sample of 180 Maya mother-daughter dyads. Mean intergenerational difference in KH was calculated and compared for each category of socioeconomic variables and a multiple regression model was adjusted to assess the association between childhood conditions and difference in KH. Results A relative increase of 1.05 cm (SD = 2.3 cm) or 0.45 standard deviations (effect size of difference) was observed in KH between generations. Place of birth and FS were significantly associated to KH. The intergenerational KH difference was 1.6 cm longer when mothers were born outside Merida but daughters were born in the city. Daughters with larger FS than their mothers associated to a decrease in KH difference (1.6 cm) compared to daughters and mothers having the same FS. Conclusions The relative represents a portion of the expected change in growth in a group that has experienced few substantial improvements in their living conditions. Slight improvements in childhood living conditions resulting from the intergenerational transition from rural to urban environments seem to be linked to a slight intergenerational increase in KH among Maya women in Merida.