Discussion
This study revealed that the 4 MTNR1B genetic variations, which were previously reported to be associated with glucose homeostasis in general populations, were associated with the gestational postprandial glucose level and with the glucose intolerance of various degrees in the pregnant Han Chinese women. Both rs1387153 and rs2166706 were found to be tightly  linked with each other and displayed the same association with gestational plasma glucose levels. The G allele of rs10830963 was shown to be the strongest signal to associate with the increased PPG level and abnormal glucose tolerance. However, rs1447352 was not found to be strongly associated with gestational glucose levels and glucose intolerance. In both general populations and our studied pregnant cohort, the rs1447352 has high values of D9 with the other 3 variants, especially with rs10830963, but the values of r 2 between rs1447352 and these variants were lower than 0.30 which indicated that rs1447352 might not be really linked with these variants. Also, the different degrees of the association are probably related to the variant's different location in the gene. The variant rs1387153 and rs2166706 located at the.11 kb upstream of the MTNR1B gene, rs10830963 is intronic, whereas rs1447352 located at the,4.5 kb downstream of the gene ( Figure 1A). Currently little knowledge about their role and regulation of MTNR1B gene expression is available. It is well known that gene upstream sequences and introns have various important regulatory functions, for example, intron-derived miRNAs are able to induce RNA interference. Hence it is intriguing for further research on how these different variants affect the gene function, especially in the gestational background. Based on GWAS, there are reports about that the G-allele of MTNR1B rs10830963 associated with defective early insulin response, beta-cell dysfunction and hepatic insulin resistance in Europeans [13,14], and Lyssenko et al. have showed the pathogenic effects of MTNR1B were likely exerted via a direct inhibitory effect on beta cell [12], the particular physiological pathway of MTNR1B in glucose metabolism has not been identified, yet it is interesting that the genetic variants within the MTNR1B region have different influence on glucose levels during pregnancy. Considering the importance of biological rhythms for metabolic regulation and the reciprocal influence of gestational hormones, the link between the MTNR1B susceptibility loci and gestational glucose metabolism may reveal new mechanisms underlying glucose homeostasis during pregnancy.
In pregnant Chinese women, we observed that rs1387153 and rs2166706 were associated with gestational FPG levels, but we could not detect a significant association between the MTNR1B variants rs10830963, rs1447352 and the gestational FPG levels in the regression analysis. Nevertheless, we observed that for each MTNR1B variant with each additional risk alleles, the mean levels of FPG were higher than those without the risk alleles in the studied women. It is also noteworthy that in the current study, the effect size of FPG in pregnant women was less than that reported in the general populations. In fact, FPG levels tend to decrease during pregnancy, likely due to the effect of pregnant hormones on blood glucose and insulin resistance. Our data indicate that MTNR1B genetic polymorphisms could be associated with gestational FPG levels in the pregnant Chinese women.
In this study, both levels of FPG and PPG were normally distributed ( Figure S1); the allelic and genotypic frequencies of all the 4 studied variants were in Hardy-Weinberg equilibrium (Table  S1); and the result of LD tests in these pregnant women was concordant with the LD pattern in the general population [20]. Since the studied sample population of pregnant women was limited to Chengdu in China, it will be necessary to confirm our findings through studies of populations of other districts and ethnicities. Interestingly, MTNR1B rs10830963 and rs1387153 were reported to be linked to the risk of GDM in Korean women [28], as well, rs10830963 was recently found to be associated with beta-cell function in a Chinese pregnant Population [29], although both studies did not test the association of the MTNR1B variants with different gestational glucose levels and glucose intolerance.
In summary, our data suggests that the genetic variants within MTNR1B gene are associated with gestational glucose levels and gestational glucose intolerance. To our knowledge, this is the first report on the association in a cohort of pregnant Chinese women. This work extended the research on MTNR1B from the general population into the context of pregnancy and provided new information on associations of MTNR1B polymorphisms in the Chinese population.  Flowchart S1 Screening for gestational glucose intolerance in pregnant Chinese women. Briefly, a stepwise approach for all pregnant women was used.

Supporting Information
Step 1 is a screening 50 g, 1 h glucose challenge test, both the fasting glucose and the 1 hour postprandial glucose levels were determined. Women with FPG $5.8 mmol/l or 1 h PPG $7.8 mmol/l were defined as a positive GCT result and would be suggested to go to step 2. Step 2 is a 100 g, 3 h OGTT. NDDG cut-off for diagnosis GDM was employed. The high-risk pregnant women with demonstrable risk factors might be suggested to undergo a random blood glucose test at the first antenatal visit. If they had FPG $7.0 mmol/l or a random PPG $11.1 mmol/l, and this result was confirmed on a subsequent day, the women would be diagnosed with GDM or DM (T1DM and previous T2DM with elevated HgA1C prior to 20 gestational weeks) without diagnostic OGTT. There were 1992 pregnant women who agreed to join the study. 196 women with high risk factors of diabetes, together with 1779 women underwent 50 g GCT. Among these women, 1209 women were negative in GCT; only 1 woman was later rescreened for 100 g OGTT due to suspected macrosomia. The other 766 women were positive in GCT, 4 of them were confirmed with fg.7 mmol/l or pg.11 mmol/l. Although the rest 762 women with positive GCT were suggested to undergo 100 g OGTT, 654 women actually underwent 100 g OGTT. Among these 654 women, 349 women were positive in 100 g OGTT result. In detail, 72 of these 349 women were GDM according to NDDG diabetes criteria, 5 were GIGT and 113 were just abnormal in one glucose level without reaching the thresholds. For the other women with high risk factors of diabetes, 7 women (T1DM and T2DM) were excluded from the current study, and 9 women directly underwent 100 g OGTT, 2 of these 9 women were normal in 100 g OGTT result. (DOC)For most of the time that it's been on sale in the U.S. market—nearly five years—the Mazda5 has been an odd one out in the market—and a niche vehicle, despite its conventional minivan silhouette.
As Mazda points out, compared to the Dodge Caravan, which kicked off the U.S. minivan craze back in 1983, the 2012 Mazda5 is actually about five inches longer—and about the same width and height. Yet it manages to package in a usable third row of seats, and has 157 hp from its four-cylinder engine while the Caravan was under 100 hp.
However minivans, as most of the U.S. market knows them, have become big and bloated, and nearly as big as the full-size Country Squire–esque wagons they were eschewing in the first place.
By sticking to a leaner, more modest minivan, Mazda has surely locked onto a healthy niche market. Over the past several years, the automaker has been quietly selling increasingly more Mazda5 models with virtually no advertising or marketing dollars. And for those who want this kind of vehicle, there aren't any alternatives: Mazda found that 29 percent of buyers for the outgoing generation of the Mazda5 seriously considered no other model when vehicle shopping. That's an enviable claim, for certain.
In looking at its current buyer set, affordability ranked near the top among reasons for purchase. So with the full redesign of the Mazda5, the brand didn't innovate; rather it took the Mazda5 package, gave it a little more refinement and quite a bit more design flair from the outside, and didn't go overboard with features and options that would drive the price up.
As we noted in our First Drive of the 2012 Mazda5, the new version of this van remains one of our favorite people-mover picks as it retains the surprising fun-to-drive qualities of the previous version--and even improves on them. But the resulting 2012 Mazda5 smacks of cost-consciousness. Its interior materials feel very basic and on a budget; there's no direct-injection engine; no power doors, hatches, or seats (though you don't need them here); and it has no USB plug, no iPod controls, and no available navigation system.
Mazda says that it's anticipating that buyers will be bringing their own portable navigation systems or nav-equipped smartphones on board, but it seems to us that an affordable nav option would have a place. At the same time, the typical family that ends up buying a Mazda5 is college-educated and makes just over $90k a year, and it seems that connectivity for their iPhones and iPods would be a priority.
Sound systems are very modest, too. The base system sounds well enough (albeit a little muddy with bass response), but it felt like an