Having a pet when you're a kid is awesome¹, but now it looks like cats have an extra benefit - they could offer protection against certain pulmonary conditions like bronchitis and pneumonia².

小时候拥有宠物是极好的，不过现在看起来养猫还有别的好处，像是可以防止某些肺部疾病，例如支气管炎和肺炎。

Before you rush off and buy your newborn an anti-asthma³ kitty, you should know there's a catch - if you happen to have mutated versions of a certain gene, feline⁴ fluff could also trigger eczema.

赶着去买新生儿抗哮喘猫咪前，你还应该知道一个问题：假如你碰巧有一个特定的突变基因，猫毛可能也会引发湿疹。

Research by a team of scientists from the Copenhagen Studies on Asthma in Childhood Research Centre (COPSAC) in Denmark has provided a possible explanation for why studies on pets and asthma are so conflicted.

针对宠物和哮喘的研究结果存在矛盾这一问题，丹麦哥本哈根儿童哮喘研究中心的研究小组提供了一个可能的解释。

So far studies have shown contradictory⁵ results - owning a pet can help prevent certain hypersensitivity disorders⁶, make no difference at all, or make them worse.

到目前为止，研究显示了几种矛盾的结果：拥有宠物可以帮助预防某些过敏性疾病，根本不会造成任何改变，或者只会加重病情。

It turns out the devil might be in the detail. And that detail is a variation of the gene 17q21.

事实证明，恶魔可能藏在细节之中，而这个细节就是基因17q21的变体。

Called TT, the genetic⁷ variant⁸ has already been found to double the risk of 'atopy' conditions such as asthma and inflammation of the bronchi, making it a prime candidate for studies looking at environmental influence on childhood development.

被称为TT的遗传基因变体已被查出使“过敏性”疾病的风险加倍，例如哮喘和支气管炎症，使其成为环境对儿童发育影响研究的主要调查因素。

In the latest study, researchers analysed the medical, genetic, and environmental information from 377 Danish children whose mothers were diagnosed with a history of asthma. This included a map of their genes⁹, and samples of allergens collected from their beds.

在最新的研究中，研究人员分析了377名丹麦儿童的医学、遗传和环境信息，他们的母亲经诊断都有哮喘病史。这些信息包括他们的基因地图，以及从他们床上收集的过敏原样本。

Just under a third of the children carried the TT variant, which should have made them more susceptible¹⁰ to developing asthma themselves.

只有不到三分之一的孩子携带了TT变体，这本应使得他们更容易患上哮喘。

On analysing the numbers, however, it turned out that having cat dander around when they were born, reduced the risk impact of the gene.

然而，分析数据后发现，孩子出生时如果家里养了猫，这一基因的风险影响就会降低。

In other words, if you're unlucky enough to have the particular gene that doubles your chances of getting asthma, getting a cat early can help mitigate¹¹ that risk.

换句话说，如果你不幸携带特定的基因使得你患哮喘的几率翻倍，那么小的时候家里养只猫可以帮助减轻这种风险。

The exact process behind the added protection isn't clear. Allergens could be directly interfering¹² with the gene's expression, or maybe it's more convoluted¹³, involving microbes in the cat's microflora.

这一现象背后的确切过程尚不清楚。过敏原可能会直接干扰基因的表达，也可能更复杂，涉及猫体内菌群的微生物。

Whatever it is that cats shed, puppies don't have it. There was no similar decrease in asthma risk for those newborns who shared their home with a dog.

不管猫咪在其中发挥了怎样的作用，小狗都无法发挥同样的作用。这体现在对于那些家里养狗的新生儿，哮喘风险并没有类似的下降。

While the research doesn't point directly to a preventative treatment for asthma, it does emphasise¹⁴ how complicated disease development can be.

虽然这项研究并没有直接指向哮喘的预防性治疗，但确实强调了疾病发展的复杂程度。

"For me, this is the core message because it's a recognition in the direction of how disease occurs," says researcher Hans Bisgaard.

研究人员汉斯·比尔加德说：“对我来说，核心信息在于它是对疾病发展方向的一种认识。

"It documents the interplay between genetics and the environment we live in, and in particular that this occurs very early in life, both during pregnancy¹⁵ and in the home."

“它记录了在遗传基因和我们生活的环境间的相互作用，尤其当这种相互作用发生在生命的早期，无论是母亲肚子里的胎儿还是家中的幼儿。”

Just to add to the problem, there could be a cost to buying junior a cat. Previous research conducted by COPSAC had found that people with mutant versions of the gene encoding a binding¹⁶ protein called filaggrin suffered an added risk of developing eczema if they had a cat.

更麻烦的一点是，给青少年买猫咪可能会付出代价。哥本哈根儿童哮喘研究中心此前研究发现，携带一种叫做聚角蛋白的结合蛋白基因变体的人，如果养了一只猫，则会增加患湿疹的风险。

Having a dog, on the other hand, offered a moderate amount of protection for those with and without the mutation¹⁷.

另一方面，对于基因突变和无基因突变的人来说，养一条狗可以提供适度的保护。

Short of getting genetic screens done and buying a pet based on our unique genetics – which, by the way, could one day be a reality – we're left with a gamble.

我们尚未完成基因筛选，也还不能根据每个人独一无二的遗传基因来买宠物，这在有朝一日可能成为现实，不过目前只能是赌一把了。

On the balance, having some kind of pet or two around growing children seems to provide a bunch of benefits, so you can't go wrong either way. But it's also possible that many of those advantages have nothing to do with the animals themselves.

总的来说，成长的孩子身边有一两只宠物似乎带来很多好处，所以你选择养宠物是没错的。不过，也有可能这些好处或者有点与动物本身没有关系。

But we have more information now about the interaction between asthma and kitties, and the good news is that even for asthma-prone people, a cat can be a very good thing.

但是现在我们有更多关于哮喘和小猫之间相互作用的信息，好消息是，即使对于容易患哮喘的人，养猫也可能是件好事。