Maternal Dietary Patterns In Pregnancy And The Associations With Gestational Diabetes Mellitus

Gestational diabetes mellitus?GDM?,defined as glucose intolerance with onset or first recognition during pregnancy,is a common pregnancy complication.The prevalence of GDM has increased dramatically during past decades and has adverse health outcomes for both mothers and their offspring.Maternal diet is potentially modifiable risk factor and plays an important role in the development of GDM.Recently,more attention has been paid to the overall effect of dietary pattern.Theoretically,dietary patterns represent a broader picture of food and nutrient consumption,and they may thus be more predictive of disease risk.However,the contribution of different foods and nutrients to the relationship between dietary pattern and GDM risk should also be considered to help explore the underlying mechanisms.Therefore,the aim of the present study is to uncover the relationship between maternal dietary pattern,foods and nutrients intake and the risk of GDM during pregnancy.The first part is to identify the dietary patterns of pregnant women,and to examine the relationship between dietary patterns and risk of GDM.The second part is to evaluate the contribution of different food and nutrient components to the association between dietary patterns and GDM based on the results of the first part.The third part is to specifically examine the association between fresh fruit intake?which was confirmed as an important contributor to the relationship between dietary pattern and GDM risk in the second part?and GDM risk.Part 1 Maternal dietary patterns in pregnancy and their associations with gestational diabetes mellitusObjective:We aimed to characterize dietary patterns in mid-pregnancy and examine their associations with GDM.Design:A total of 2,755 Chinese pregnant women from the Tongji Maternal and Child Health Cohort were included in the present study.Dietary intakes were assessed using a validated semi-quantitative food frequency questionnaire?FFQ?at 22-26 weeks gestation.Dietary patterns were derived from a principal component factor analysis.GDM was diagnosed based on the results of a 75-g,2-h oral glucose tolerance test at 24-28 weeks gestation.Results:GDM occurred in 248?9.0%?of 2,755 pregnant women.Five dietary patterns were extracted:beans-vegetables,nuts-whole grains,fish-meat-eggs,organ-poultry-seafood,and rice-wheat-fruits.Higher fish-meat-eggs scores were associated with an increased risk of GDM(OR for highest quartile vs.lowest quartile:1.83;95%CI 1.21 to 2.79;P_trend=0.007),each SD of fish-meat-eggs score was associated with a 32%?95%CI:12%,54%?increment in OR of GDM.Higher rice-wheat-fruits scores were associated with reduced risk of GDM(OR for quartile 3 vs.lowest quartile:0.54;95%CI 0.36 to 0.83;P_trend=0.010),each SD of rice-wheat-fruits score was associated with a 22%?95%CI:12%,32%?decrement in OR of GDM.The adjusted results showed that per SD increase in the fish-meat-eggs score,the fasting,1-h and 2-h plasma glucose reading increased by 0.02 mmol/L?95%CI:0.00 to-0.03??0.14 mmol/L?95%CI:0.08 to 0.20?and 0.07mmol/L?95%CI:0.03 to 0.12?,respectively.With an SD increase in the rice-wheat-fruits score,fasting,1-h and 2-h0.01 mmol/L?95%CI:-0.03 to 0.00??0.10 mmol/L?95%CI:-0.16 to-0.04?and 0.09mmol/L?95%CI:-0.14 to-0.05?,respectively.And stratified analyses showed the association was stronger in overweight women and in women with a family history of diabetes.No associations were seen for the beans-vegetables,nuts-whole grains,or organ-poultry-seafood patterns in relation to GDM or plasma glucose level.Conclusions:These findings suggest that higher intakes of animal foods,characterized by the fish-meat-eggs pattern,are associated with greater risk of GDM and that this association is stronger in overweight women and in women with a family history of diabetes.By contrast,higher intakes of plant foods,characterized by the rice-wheat-fruits pattern,are associated with lower risk of GDM.Part 2 The contribution of nutrients and food components to the associations between dietary patterns and GDMObjective:We aimed to examine the contribution of different foods and nutrients to the association between dietary patterns and GDM.Methods:Subjects recruitment was described in part one.The ORs and 95%CIs of GDM for each category of dietary pattern compared with the lowest category were estimated using logistic regression models.The intakes of macronutrients?eg,total fat,animal fat,vegetable fat,total protein,animal protein,vegetable protein,total carbohydrate,and ratio of total protein to total carbohydrate?,other nutrients?eg,dietary fiber,cholesterol,vitamin C,vitamin E,magnesium,potassium,calcium,total iron,heme iron and non-heme iron?,and each food or food group component of each dietary pattern were adjusted in the model one by one to explore potential dietary contributors for the association between dietary patterns and GDM.,Result:The results showed that high fish-meat-eggs scores were positively related to protein intake and inversely related to carbohydrate intake,high rice-wheat-fruits scores were positively related to carbohydrate intake and inversely related to protein intake.The association of the fish-meat-eggs score with GDM risk for comparisons of highest with lowest quartiles was no longer significant after additional adjustment for total protein?percentage of energy??OR:1.42 95%CI:0.90,2.22?,or animal protein?percentage of energy??OR:1.51 95%CI:0.94,2.44?,or total carbohydrate?percentage of energy??OR:1.48 95%CI:0.92,2.36?,or ratio of total protein to total carbohydrate?OR:1.35 95%CI:0.84,2.16?,which indicated that protein and carbohydrate may be the main contributors to the observed association between the fish-meat-eggs score and GDM risk.Moreover,for rice-wheat-fruits dietary pattern,the association with GDM was attenuated substantially after adjusting for total protein intake and ratio of total protein to total carbohydrate,respectively.Additionally,the association of the fish-meat-eggs score with GDM risk for comparisons of highest with lowest quartiles was no longer significant after additional adjustment for cholesterol?OR:1.56 95%CI:0.99,2.48?.For rice-wheat-fruits dietary pattern,the association with GDM was attenuated substantially after adjusting for fruit intake.Conclusions:Our results suggested that a maternal dietary pattern characterized by high-protein and low-carbohydrate intake in pregnancy was associated with a higher risk of GDM in Chinese women.Additionally,fruit and cholesterol intake may play a key role in the relationship between dietary patterns and GDM.Part 3 Fresh fruit intake in pregnancy and the association with gestational diabetes mellitusObjective:We aimed to assess the relation of fresh fruit intake and GDM incidence in Chinese pregnant women.Methods:We included 3,300 eligible women from the Tongji Maternal and Child Health Cohort.Dietary surveys and GDM screening methods were described in part one.Logistic regression model and multivariate linear regression model were used to analyze the relationship between fruit intake and GDM and blood glucose level,respectively.Results:GDM occurred in 378?11.5%?of 3,300 pregnant women.The average fresh fruit consumption was 381.7g/d.The adjusted ORs?95%CIs?for GDM from the lowest to highest quintile of whole fruit consumption were 1.00?referent?,0.80?0.56,1.12?,0.74?0.52,1.05?,0.63?0.44,0.92?,and 0.41?0.27,0.62?,respectively;P_trend<0.001.The adjusted results showed that per 100g increase in total fruit consumption,the 1-h and 2-h plasma glucose reading decreased by 0.050 mmol/L?95%CI-0.081 to-0.019?and 0.035 mmol/L?95%CI-0.059 to-0.012?,respectively?all P<0.05?.In addition,the stratified analysis results showed that greater consumption of low/high glycemic index fruits and low glycemic load fruits were both associated with a lower risk of GDM,but not high glycemic load fruits.Conclusions:Our findings suggested an inverse association of fresh fruit intake with the risk of GDM in Chinese pregnant women.However,excessive fruit consumption of high glycemic load values should not be recommended.