众所周知，成人期肥胖症容易引起高血压，冠心病，糖尿病，脂肪肝及胆结石等各种危害。研究发现，成年期肥胖的人常常在儿童期超重或肥胖，而儿童早期和儿童期的正常体重和体重增长速率和成人期肥胖症的低发生率相关。今年1月份发表于美国儿科学会出版的《PEDIATRICS》期刊上的研究更是明确发现，儿童早期和青少年时期是避免成人期肥胖症的“关键窗口”。

Adults who are obese are more likely to develop a number of potentially serious health problems, including type 2 diabetes, high blood pressure, high cholesterol, heart disease, stroke, and sleep apnea. Earlier studies found obese adults are often overweight and obese during childhood. Healthy early childhood body weight and weight gain often link with lower adult obesity rates. A new study published on January Pediatrics suggests there are two "critical windows" to change to path to weight gain and avoid obesity.

这项研究追溯了超过2700个芬兰成年人31年的身体质量指数（BMI），时间跨度从儿童期（3-18岁）到成人期 （34-49岁）。统计数据分析发现，成人期肥胖的人与不肥胖的人相比，他们6岁之前BMI值就已经偏高，每年的BMI波动变化相对较大。研究者同时发现，儿童期肥胖和超重的人群中有一部分人在成人期体重正常，他们的BMI数值分别从女孩的16岁和男孩的21岁开始维持稳定的平台期。但是在儿童期肥胖和超重的另一部分人的BMI数值持续上升直到女性的25岁和男性的27岁，这部分人在成年期持续肥胖。

This research analysed the body mass index (BMI) trajectories of more than 2700 participants in Finland from their childhood to adulthood. It is found that compared to people who will avoid adult obesity, people who develop obesity as an adult had a higher BMI already at age 6 and had more yearly change in BMI in childhood. In overweight or obese children who managed to become non-obese adults, researchers found that BMI levels started to plateau from 16 years for females and 21 years for males, whereas BMI kept increasing until age 25 (for males) and 27 (for females) for overweight or obese children who persisted with obesity into adulthood.

无独有偶，另一个发表在美国心脏协会《Circulation》期刊上的研究也发现了BMI增长轨迹和成人期肥胖的关系。数据显示，成人期肥胖者在儿童期的BMI高于同龄人；在17岁时BMI数值的增长速率和成人期肥胖的关联度最高。

This finding is consistent with earlier studies published in Circulation that identified the link between the early-life BMI trajectories and adult obesity. Data has shown that people who became obese as adults tended to have higher BMI than their peers during childhood. The biggest association between BMI growth and adult obesity is at 17 years old.

从这两个研究结果中我们不难发现，儿童早期是预防未来成人期肥胖的重要“关键窗口”。在6岁以前，就要着重于努力保持正常的BMI轨迹并且做到每年正常的波动变化。第二个解决成年肥胖问题的“关键窗口”开始于青春期和成人早期。如果之前存在有超重或肥胖的问题， 那么在青春期的16岁（女生）和21岁（男生）开始能做到BMI稳定，那么有希望在成人期远离肥胖的困扰。 反之，如果继续BMI持续上升到25岁（女生）和27岁（男生），则很有可能发生成人期肥胖症。

These findings suggest that early childhood is a key period for preventing obesity later on. Great efforts should be made to achieve a healthy BMI by age 6 and to maintain a healthy BMI gain throughout childhood. A second "critical window" to correct adverse BMI trajectories begins in adolescence for females and early adulthood for males. If BMI levels started to stabilize from 16 years for females and 21 years for males, while BMI kept increasing until age 25 (for males) and 27 (for females) for overweight or obese children who persisted with obesity into adulthood.  

总而言之，预防肥胖，我们得从娃娃抓起。6岁前是第一个关键节点，青春期和成人早期是第二个关键窗口期。

附录：BMI的计算和儿童肥胖的标准

身体质量指数（BMI）是在 ≥ 2岁的儿童中评价超重及肥胖的公认标准指标。 计算公式是BMI = 体重（kg）/ 身高(m)2

下面附录了WHO制定的按年龄性别的BMI生长标准图

以下定义用于对2-20岁儿童的体重状态进行分类：

● 体重低下–按年龄和性别划分，BMI < 第5百分位数

● 体重正常–按年龄和性别划分，BMI位于第5和第85百分位数之间

● 超重–按年龄和性别划分，BMI位于第85和第95百分位数之间

● 肥胖–按年龄和性别划分，BMI≥第95百分位数

● 重度肥胖–BMI≥第95百分位数的120%，或者BMI≥35 kg/m2