Objectives

Adult obesity may be positively associated with risks of rheumatoid arthritis (RA), but associations with early life body size are unknown. We examined whether birthweight, childhood body mass index (BMI), height, and changes in BMI and height were associated with risks of adult RA.

Method

A cohort of 346 602 children (171 127 girls) from the Copenhagen School Health Records Register, born in 1930–1996, with measured weights and heights from 7 to 13 years of age, were included. Information on RA, including serological status, came from national registers from 1977 to 2017. Cox regressions were performed.

Results

During a median of 35.1 years of observation time per person, 4991 individuals (3565 women) were registered with RA. Among girls, per BMI z-score, risks of RA and seropositive RA increased by 4–9% and 6–10%, respectively. Girls with overweight had higher risks of RA than girls without overweight. Girls who became overweight by 13 years of age had increased risks of RA compared to girls without overweight at 7 or 13 years (hazard ratio = 1.40, 95% confidence interval 1.19–1.66). For boys, associations between BMI and RA (including seropositive RA) were not statistically significant. Height was not associated with RA (any type) in girls. Taller boys had higher risks of RA, especially seropositive RA. Birthweight was not associated with RA.

Conclusions

Among women, childhood adiposity was associated with increased risks of RA. Among men, childhood height was positively associated with risks of RA. These findings support the hypothesis that early life factors may be important in the aetiology of RA.

中文翻译：

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出生体重、体型和儿童时期的生长以及类风湿性关节炎的风险：一项大型丹麦队列研究

目标

成人肥胖可能与类风湿性关节炎 (RA) 的风险呈正相关，但与生命早期体型的关联尚不清楚。我们检查了出生体重、儿童期体重指数 (BMI)、身高以及 BMI 和身高的变化是否与成人 RA 的风险相关。

方法

来自哥本哈根学校健康记录登记册的 346 602 名儿童（171 127 名女孩）出生于 1930 年至 1996 年，测量的体重和身高年龄在 7 至 13 岁之间。有关 RA 的信息，包括血清学状态，来自 1977 年至 2017 年的国家登记册。进行了 Cox 回归。

结果

在每人平均 35.1 年的观察时间中，有 4991 人（3565 名女性）登记患有 RA。在女孩中，根据 BMI z 分数，RA 和血清阳性 RA 的风险分别增加了 4-9% 和 6-10%。超重的女孩比没有超重的女孩患 RA 的风险更高。与 7 岁或 13 岁时没有超重的女孩相比，13 岁时超重的女孩患 RA 的风险增加（风险比 = 1.40，95% 置信区间 1.19–1.66）。对于男孩，BMI 和 RA（包括血清阳性 RA）之间的关联没有统计学意义。身高与女孩的 RA（任何类型）无关。个子较高的男孩患 RA 的风险较高，尤其是血清阳性 RA。出生体重与 RA 无关。

结论

在女性中，儿童肥胖与 RA 风险增加有关。在男性中，儿童身高与 RA 风险呈正相关。这些发现支持早期生活因素可能在 RA 的病因学中起重要作用的假设。