Supplementary Material for: Association between Carbonic Anhydrase VI (CA VI) gene copy number and dental caries experience

The current study examined the association between the carbonic anhydrase VI (CA VI) copy number variations (CNVs) and dental caries experience in adults. In total, 202 of 35-72 years old subjects participating in the Lithuanian National Oral Health Survey (LNOHS) agreed to provide saliva samples, thus their data were included in the current study. Information about sociodemographic, environmental, and behavioural determinants was acquired via the self-administered World Health Organisation (WHO) questionnaire. Fluoride levels in the drinking water were recorded based on information provided by water suppliers. Dental caries experience was recorded by one calibrated examiner using the WHO criteria for recording caries on smooth (including proximal, buccal, and oral) or occlusal surfaces. Caries experience was measured as the total number of decayed (D3), missing (M), filled (F) surfaces (D3MFS). DNA was extracted from saliva samples to examine CA VI CNVs using the QX200 droplet digital PCR system. Negative binomial regression and Poisson regression analyses were employed for data analyses. Based on multivariable regression analyses, higher copy number of CA VI were associated with higher caries experience on smooth surfaces (IRR 1.04, 95% CI 1.005 – 1.08) and occlusal surfaces (IRR 1.02, 95% CI 1.003 – 1.04). Positive associations between higher copy number of CA VI and higher caries experience on smooth and occlusal surfaces were found, suggesting that the CA VI coding gene may be associated with caries development. Future studies are needed to validate our results and to examine the underlying mechanisms of such associations.本研究探讨了碳酸酐酶VI（carbonic anhydrase VI, CA VI）拷贝数变异（copy number variations, CNVs）与成年人群龋病经历的关联。本研究共纳入参与立陶宛国家口腔健康调查（Lithuanian National Oral Health Survey, LNOHS）的35至72岁受试者，其中202名同意提供唾液样本，其相关数据被纳入本研究。研究通过受试者自行填写的世界卫生组织（World Health Organisation, WHO）问卷，收集社会人口学、环境及行为相关影响因素信息；饮用水氟化物水平依据供水供应商提供的数据进行记录。由1名经过校准的口腔检查者按照WHO的龋病记录标准，对光滑面（包括邻面、颊面与口面）或咬合面的龋损情况进行评估，龋病经历以龋坏（D3）、缺失（M）、充填（F）的牙面数总和（D3MFS）进行量化。从唾液样本中提取DNA后，采用QX200液滴数字PCR系统检测CA VI的CNVs。数据分析采用负二项回归与泊松回归方法。多变量回归分析结果显示，CA VI拷贝数更高与光滑面龋病经历更严重呈显著正相关（发病率比（incidence rate ratio, IRR）=1.04，95%置信区间（95% confidence interval, 95% CI）：1.005~1.08），与咬合面龋病经历更严重亦存在显著正相关（IRR=1.02，95%CI：1.003~1.04）。本研究发现CA VI拷贝数更高与光滑面及咬合面龋病经历更严重存在正向关联，提示编码CA VI的基因可能与龋病的发生发展密切相关。未来仍需开展相关研究以验证本研究结果，并探讨此类关联的潜在作用机制。