TY - JOUR

T1 - Association of milk intake with hay fever, asthma, and lung function

T2 - a Mendelian randomization analysis

AU - Skaaby, Tea

AU - Kilpeläinen, Tuomas O.

AU - Mahendran, Yuvaraj

AU - Huang, Lam Opal

AU - Sallis, Hannah

AU - Thuesen, Betina H.

AU - Kårhus, Line Lund

AU - Leth-Møller, Katja Biering

AU - Grarup, Niels

AU - Hansen, Torben

AU - Pedersen, Oluf

AU - Burgess, Stephen

AU - Munafò, Marcus R.

AU - Linneberg, Allan

N1 - Publisher Copyright: © 2021, Springer Nature B.V.

PY - 2022

Y1 - 2022

N2 - Background: Previous observational studies have indicated a protective effect of drinking milk on asthma and allergy. In Mendelian Randomization, one or more genetic variants are used as unbiased markers of exposure to examine causal effects. We examined the causal effect of milk intake on hay fever, asthma, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) by using the lactase rs4988235 genotype associated with milk intake. Methods: We performed a Mendelian Randomization study including 363,961 participants from the UK Biobank. Results: Observational analyses showed that self-reported milk-drinkers vs. non-milk drinkers had an increased risk of hay fever: odds ratio (OR) = 1.36 (95% CI 1.32, 1.40, p < 0.001), asthma: OR = 1.33 (95% CI 1.38, 1.29, p < 0.001), yet a higher FEV1: β = 0.022 (SE = 0.004, p < 0.001) and FVC: β = 0.026 (SE = 0.005, p < 0.001). In contrast, genetically determined milk-drinking vs. not drinking milk was associated with a lower risk of hay fever: OR = 0.791 (95% CI 0.636, 0.982, p = 0.033), and asthma: OR = 0.587 (95% CI 0.442, 0.779, p = 0.001), and lower FEV1: β = − 0.154 (standard error, SE = 0.034, p < 0.001) liter, and FVC: β = − 0.223 (SE = 0.034, p < 0.001) liter in univariable MR analyses. These results were supported by multivariable Mendelian randomization analyses although not statistically significant. Conclusions: As opposed to observational results, genetic association findings indicate that drinking milk has a protective effect on hay fever and asthma but may also have a negative effect on lung function. The results should be confirmed in other studies before any recommendations can be made.

AB - Background: Previous observational studies have indicated a protective effect of drinking milk on asthma and allergy. In Mendelian Randomization, one or more genetic variants are used as unbiased markers of exposure to examine causal effects. We examined the causal effect of milk intake on hay fever, asthma, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) by using the lactase rs4988235 genotype associated with milk intake. Methods: We performed a Mendelian Randomization study including 363,961 participants from the UK Biobank. Results: Observational analyses showed that self-reported milk-drinkers vs. non-milk drinkers had an increased risk of hay fever: odds ratio (OR) = 1.36 (95% CI 1.32, 1.40, p < 0.001), asthma: OR = 1.33 (95% CI 1.38, 1.29, p < 0.001), yet a higher FEV1: β = 0.022 (SE = 0.004, p < 0.001) and FVC: β = 0.026 (SE = 0.005, p < 0.001). In contrast, genetically determined milk-drinking vs. not drinking milk was associated with a lower risk of hay fever: OR = 0.791 (95% CI 0.636, 0.982, p = 0.033), and asthma: OR = 0.587 (95% CI 0.442, 0.779, p = 0.001), and lower FEV1: β = − 0.154 (standard error, SE = 0.034, p < 0.001) liter, and FVC: β = − 0.223 (SE = 0.034, p < 0.001) liter in univariable MR analyses. These results were supported by multivariable Mendelian randomization analyses although not statistically significant. Conclusions: As opposed to observational results, genetic association findings indicate that drinking milk has a protective effect on hay fever and asthma but may also have a negative effect on lung function. The results should be confirmed in other studies before any recommendations can be made.

KW - Allergic disease

KW - Asthma

KW - Hay fever

KW - Lung function

KW - Milk

U2 - 10.1007/s10654-021-00826-5

DO - 10.1007/s10654-021-00826-5

M3 - Journal article

C2 - 34978666

AN - SCOPUS:85122145830

VL - 37

SP - 713

EP - 722

JO - European Journal of Epidemiology

JF - European Journal of Epidemiology

SN - 0393-2990

ER -