TY - JOUR
T1 - Association of lactase persistence genotype with milk consumption, obesity and blood pressure
T2 - A Mendelian randomization study in the 1982 Pelotas (Brazil) Birth Cohort, with a systematic review and meta-analysis
AU - Hartwig, Fernando Pires
AU - Horta, Bernardo Lessa
AU - Smith, George Davey
AU - De Mola, Christian Loret
AU - Victora, Cesar Gomes
N1 - Publisher Copyright:
© The Author 2016. Published by Oxford University Press on behalf of the International Epidemiological Association
PY - 2016/10
Y1 - 2016/10
N2 - Background: Milk intake has been associated with lower blood pressure (BP) in observational studies, and randomized controlled trials suggested that milk-derived tripeptides have BP-lowering effects. Milk intake has also been associated with body mass index (BMI). Nevertheless, it is unclear whether increasing milk consumption would reduce BP in the general population. Methods: We investigated the association of milk intake with obesity and BP using genetically-defined lactase persistence (LP) based on the rs4988235 polymorphism in a Mendelian randomization design in the 1982 Pelotas (Southern Brazil) Birth Cohort. These results were combined with published reports identified through a systematic review using meta-analysis. Results: In the 1982 Pelotas Birth Cohort, milk intake was 42 [95% confidence interval (CI): 18; 67) ml/day higher in LP individuals. In conventional observational analysis, each 1-dl/day increase in milk intake was associated with 0.26 (95% CI: 0.33; 0.19) kg/m2 in BMI and 0.31 (95% CI: 0.46; 0.16) and -0.35 (95% CI: 0.46; 0.23) mmHg in systolic and diastolic BP, respectively. These results were not corroborated when analysing LP status, but confidence intervals were large. In random effects meta-analysis, LP individuals presented higher BMI [0.17 (95% CI: 0.07; 0.27) kg/m2] and higher odds of overweight-obesity [1.09 (95% CI: 1.02; 1.17)]. There were no reliable associations for BP. Conclusions: Our study supports that LP is positively associated with obesity, suggesting that the negative association of milk intake with obesity is likely due to limitations of conventional observational studies. Our findings also do not support that increased milk intake leads to lower BP.
AB - Background: Milk intake has been associated with lower blood pressure (BP) in observational studies, and randomized controlled trials suggested that milk-derived tripeptides have BP-lowering effects. Milk intake has also been associated with body mass index (BMI). Nevertheless, it is unclear whether increasing milk consumption would reduce BP in the general population. Methods: We investigated the association of milk intake with obesity and BP using genetically-defined lactase persistence (LP) based on the rs4988235 polymorphism in a Mendelian randomization design in the 1982 Pelotas (Southern Brazil) Birth Cohort. These results were combined with published reports identified through a systematic review using meta-analysis. Results: In the 1982 Pelotas Birth Cohort, milk intake was 42 [95% confidence interval (CI): 18; 67) ml/day higher in LP individuals. In conventional observational analysis, each 1-dl/day increase in milk intake was associated with 0.26 (95% CI: 0.33; 0.19) kg/m2 in BMI and 0.31 (95% CI: 0.46; 0.16) and -0.35 (95% CI: 0.46; 0.23) mmHg in systolic and diastolic BP, respectively. These results were not corroborated when analysing LP status, but confidence intervals were large. In random effects meta-analysis, LP individuals presented higher BMI [0.17 (95% CI: 0.07; 0.27) kg/m2] and higher odds of overweight-obesity [1.09 (95% CI: 1.02; 1.17)]. There were no reliable associations for BP. Conclusions: Our study supports that LP is positively associated with obesity, suggesting that the negative association of milk intake with obesity is likely due to limitations of conventional observational studies. Our findings also do not support that increased milk intake leads to lower BP.
KW - Blood pressure
KW - Body mass index
KW - Lactase persistence
KW - Mendelian randomization
KW - Milk
KW - Obesity
UR - http://www.scopus.com/inward/record.url?scp=85013353284&partnerID=8YFLogxK
U2 - 10.1093/ije/dyw074
DO - 10.1093/ije/dyw074
M3 - Artículo
C2 - 27170764
AN - SCOPUS:85013353284
SN - 0300-5771
VL - 45
SP - 1573
EP - 1587
JO - International Journal of Epidemiology
JF - International Journal of Epidemiology
IS - 5
ER -