美国人均寿命连续两年下滑，专家说这值得关注
美国国家卫生统计中心 21 日发布的报告显示，美国人口的寿命平均预期为 78.6 岁，比上一年的统计数据下降 0.1 岁，连续两年下滑。
上一次出现连续下降还要追溯到 1962 年和 1963 年。
需要明确的是，这里我们说的人口平均寿命都属于“预测值”，人口统计学家通过建立预测模型，取部分有代表性的样本，每年入户观察还活着的某年龄段的人口数量，这一年还活着的概率，推算出生命表。统计已经死亡的实际年龄并不能推算出现在活着的人的预期寿命，因此不具有现世意义。
世界卫生组织认为：人的寿命长短，有 60% 取决于自己，10% 取决于遗传，8% 取决于医疗条件，7% 取决于气候因素，而有 15% 取决于社会因素，这与各国的经济、社会发展程度有关。
以美国为例，78.6 岁属于什么水平？和其他发达国家相比，确实是低了一些。意大利、法国、加拿大、英国、德国的人口平均寿命预期都超过 80 岁，最长寿的是日本人，国民平均寿命为 83.8 年（2015 年中国的人口平均寿命预期为 75.99 岁，供参考）。
美国国家卫生统计中心的死亡和预防统计处主管鲍勃?安德森认为，“不能认为这是一种趋势，因为趋势至少需要两个以上的数据点支持”。但他也承认，连续两年下降是值得关注的。
从报告中论述的主要死亡原因来看，排在前十的几乎没有变化，并且占死亡总数的 74.1%。但其中七项（心脏病、癌症、慢性下呼吸道疾病、中风、糖尿病、流行性感冒、肺炎、肾脏疾病）的占比在下降，意外伤害、阿尔兹海默症和自杀率的死亡比例增加。
其中药物过量（被归类于意外伤害）被认为是一个重要的变动因素，去年有 63600 美国人因为药物滥用死亡。2014 年- 2016 年期间因为嗑药过度导致的死亡以每年 18% 的速度上升，而在 2006 年- 2014 年之间，这一数据为 3%。美国总统特朗普在今年十月说这已经上升到国家危机的层面了。
“没人见识过像现在（那么坏）的情况，作为美国人，我们不能再这么放任下去，”特朗普在一次电视讲话中表示，“是时候将社区从毒品中解放出来，我们要做终结类鸦片（opioid）药物流行的一代，我们能做到。”非常特朗普式的发言。
问题主要出在年轻人和中年人身上，从报告的人群分析看，美国的老年人群体寿命更长，主要是年轻人和中年人群的高死亡率拉低了整体数据。
题图来源：GIPHY
Life expectancy in the U.S. is falling — and drug overdose deaths are soaring
Life expectancy in the U.S. has fallen for the second year in a row, the first time it’s dropped for two consecutive years in more than half a century.
People born in the U.S. in 2016 could expect to live 78.6 years on average, down from 78.7 the year before, according to a new report released Thursday by the Centers for Disease Control and Prevention. The most common cause of death: heart disease.
The report also found death rates — calculated from the number of deaths per 100,000 people — actually rose among young adults between 2015 and 2016. And while the authors didn’t draw a direct link, another report also released Thursday by the CDC found an estimated 63,600 people died of drug overdoses in 2016. Two-thirds of those deaths were caused by opioids. Adults between the ages of 25 and 54 had the highest rate of drug overdose death.
Here’s a look at the findings:
Most common causes of death
Heart disease was the leading cause of death, followed by cancer, unintentional injuries, chronic lower respiratory diseases, stroke, Alzheimer’s disease, diabetes, influenza and pneumonia, kidney disease, and suicide.
One key point: Unintentional injuries climbed to the third leading cause of death in 2016, swapping spots with chronic lower respiratory diseases. It’s worth noting that most drug overdose deaths are classified as unintentional injuries.
MEGAN THIELKING / STAT. SOURCE: MORTALITY IN THE UNITED STATES, 2016. NATIONAL CENTER FOR HEALTH STATISTICS.Black men are dying at alarmingly high rates
Life expectancy isn’t falling for women — just for men. Life expectancy for women at birth is 81.1 years, compared to 76.1 years for men.
The death rate for the general population actually declined slightly in 2016, but that drop wasn’t seen across all racial and ethnic groups. Death rates among black men climbed 1 percent in 2016, while death rates among white women actually fell 1 percent. There weren’t any big changes in death rates among black women, white men, or Hispanic men or women.
MEGAN THIELKING / STAT. SOURCE: MORTALITY IN THE UNITED STATES, 2016. NATIONAL CENTER FOR HEALTH STATISTICS.Drug overdose deaths continue to climb
Drug death rates are increasing much faster than they have in recent years. Overdose death rates climbed roughly 10 percent per year between 1999 and 2006. Then there was a relative lull: Between 2006 and 2014, they increased roughly 3 percent each year.
But from 2014 to 2016, death rates tied to drug overdoses jumped 18 percent each year.
MEGAN THIELKING / STAT. SOURCE: DRUG OVERDOSE DEATHS IN THE UNITED STATES, 1999–2016. NATIONAL CENTER FOR HEALTH STATISTICS.Deaths due to synthetic opioids are rising
The rate of overdose deaths involving synthetic opioids other than methadone — a category that includes fentanyl, fentanyl analogs, and tramadol — doubled between 2015 and 2016. The rate of drug overdose deaths involving natural and semisynthetic opioids, such as oxycodone and hydrocodone, also rose, while overdoses involving methadone declined.
MEGAN THIELKING / STAT. SOURCE: DRUG OVERDOSE DEATHS IN THE UNITED STATES, 1999–2016. NATIONAL CENTER FOR HEALTH STATISTICS.