Direct and BMI-mediated effect of birthweight on childhood cardio-metabolic health-a birth cohort study

Data de publicação: 01/10/2019

Autores da FMUP

• Milton Severo Barros Da Silva

  Autor

• José Henrique Dias Pinto De Barros

  Autor

• Ana Cristina Correia Dos Santos

  Autor

Participantes de fora da FMUP

• Fonseca, MJ
• Lawlor, DA

Unidades de investigação

• Ciências da Saúde Pública e Forenses, e Educação Médica

Abstract

Background Different directions of the association of birthweight with cardio-metabolic health have been found, especially in children, which may be explained by the mediating effect of attained adiposity. We aimed to untangle direct and BMI-mediated associations of birthweight with childhood cardio-metabolic indicators. Methods Children from Generation XXI birth cohort were included (n = 4881). Birthweight was abstracted from clinical files. At age 4 and 7, children were re-evaluated. Glucose, triglycerides, LDL-cholesterol, systolic (SBP) and diastolic blood pressure (DBP) z-scores were the cardio-metabolic traits analyzed. Regression coefficients and respective 95% confidence intervals [beta (95%CI)] were computed using path analysis. Results Birthweight had inverse total effect on SBP at age 4 [-0.005 (-0.010; -0.001)] and 7 [-0.011 (-0.017; -0.006)] and DBP at 7 [-0.008 (-0.012; -0.004)]. Direct effects were found for SBP at 4 [-0.013 (-0.018; -0.009)] and 7 [-0.014 (-0.019; -0.009)], and DBP at 7 [-0.010 (-0.015; -0.006)], explaining the inverse total effects. Positive BMImediated indirect effects were found for all cardio-metabolic traits: higher birthweight was associated with higher childhood BMI, which in turn was associated with higher levels of cardio-metabolic traits. Conclusions Positive BMI-mediated effect of birthweight on all cardio-metabolic traits was found. However, direct effects were in the opposite direction, significant for blood pressure, which may explain the diversity of results observed in the literature. Combining the direct and BMI-mediated effects, higher birthweight was associated with lower blood pressure at age 7 and have no effect on other cardio-metabolic traits.

Keywords

• INSULIN-RESISTANCE; BLOOD-PRESSURE; EARLY GROWTH; FIT INDEXES; LATER LIFE; CHILDREN; OBESITY; FETAL; HYPERTENSION; GLUCOSE