当姐姐的总是抱怨妹妹运气太好。现在看来，她们的抱怨也不是无中生有。有研究发现，比起家里排行最大的姐姐，妹妹们更有可能身材苗条。

　　The study – the largest of its kind – suggests that birth order may play an important role in determining weight. And the researchers warned that firstborns could be at risk of other health problems too.

　　这是该领域内规模最大的一次研究，研究结果表明，出生顺序或许很大程度上决定了体重。研究员同时警告称，长子长女还有可能出现其他健康问题。

　　The scientists looked at data on the health of 13,400 pairs of sisters and found that firstborn women were, on average, 29 per cent more likely to be overweight and 40 per cent more likely to be obese than second-born sisters. The findings back up similar research on men that found firstborn males were more likely to be overweight than younger brothers.

　　科学家们比对了13400对姐妹的健康数据，结果发现，平均而言，与排行老二的妹妹相比，排行老大的姐姐超重的可能性高29%，肥胖的可能性高40%。这一发现与另一项针对男性的相似研究的结果相符，后者研究发现，比起弟弟，排行老大的哥哥超重的可能性更大。

　　研究:长女肥胖几率较次女高4成

　　The latest research examined data from pregnant Swedish women, gathered between 1991 and 2009. Weighed when they were between ten and 12 weeks pregnant, firstborn women were 1lb 4oz heavier on average than second-born sisters. This meant their body mass index (BMI) was 2.4 per cent higher. Firstborn sisters were only negligibly taller, measuring an additional 1.2mm on average.

　　最新研究比对了1991年至2009年间收集的瑞典孕妇的体重数据。研究员们分别在孕妇怀孕10周和12周时测量了她们的体重，发现排行老大的姐姐比排行老二的妹妹平均重1磅4盎司（0.57千克）。这表明，姐姐的身体质量指数（BMI）比妹妹高了2.4%。而姐姐平均身高只比妹妹高了1.2毫米，可以忽略不计。

　　The researchers also noted a considerable increase in average weight over the 18-year period, rising by four ounces per year.

　　研究员们也注意到，18年间，她们的平均体重有显著的增长，每年增重4盎司（约0.11千克）。

　　The experts, from the University of Auckland in New Zealand and Uppsala University in Sweden, said it was unclear why older sisters seemed to be heavier. But they said the findings could explain why obesity figures appear to be soaring.

　　新西兰奥克兰大学（University of Auckland）和瑞典乌普萨拉大学（Uppsala University）的专家表示，姐姐更重的原因尚不清楚，但这一发现可以解释为何超重者的人数在飙升。

　　The scientists also said there is mounting evidence that firstborns are more at risk of health problems such as diabetes and high blood pressure in later life than their siblings. But the underlying causes for these differences are far from clear, they added.

　　科学家们还说，越来越多的证据表明，在日后的生活中，长子长女比他们的弟弟妹妹更容易受到健康问题的困扰，例如糖尿病、高血糖等。不过还表示，造成这些差异的潜在原因还不得而知。

　　Vocabulary

　　negligibly: 极小地，可以忽略不计地

　　epidemiology: 流行病学