Department of Epidemiology and Public Health, Swiss Tropical & Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
Federal Office of Meteorology and Climatology MeteoSwiss, Switzerland.
Sci Total Environ. 2021 Aug 10;781:146382. doi: 10.1016/j.scitotenv.2021.146382. Epub 2021 Mar 16.
Longitudinal shifts in pollen onset, duration, and intensity are public health concerns for the growing number of individuals with pollen sensitization. National analyses of long-term pollen changes are influenced by how a plant's main pollen season (MPS) is defined. Prior Swiss studies have inconsistently applied MPS definitions, leading to heterogeneous conclusions regarding the magnitude, directionality, and significance of multi-decade pollen trends. We examined national pollen data in Switzerland between 1990 and 2020, applying six MPS definitions (2 percentage-based and 4 threshold-based) to twelve relevant allergenic plants. We analyzed changes in pollen season using both linear regression and locally estimated scatterplot smoothing (LOESS). For 4 of the 12 plant species, there is unanimity between definitions regarding earlier onset of pollen season (p < 0.05), with magnitude of 31-year change dependent on specific MPS definition (hazel: 9-18 days; oak: 5-13 days; grasses: 8-25 days; and nettle/hemp: 6-25 days). There is also consensus (p < 0.05) for modified MPS duration among hazel (21-104% longer), nettle/hemp (8-52% longer), and ash (18-38% shorter). Between-definition agreement is highest for MPS intensity analysis, with consensus for significant increases in seasonal pollen quantity (p < 0.05) among hazel, birch, oak, beech, and nettle/hemp. The largest relative intensification is noted for hazel (110-146%) and beech (162-237%). LOESS analysis indicates that these multi-decade pollen changes are typically nonlinear. The robustness of MPS definitions is highly dependent on annual pollen accumulation, with definition choice particularly influential for long-term analysis of low-pollen plants such as ragweed. We identify systematic differences between MPS definitions and suggest future aerobiologic studies apply multiple definitions to minimize bias. In summary, national pollen onset, duration, and intensity have shifted for some plants in Switzerland, with MPS definition choice affecting magnitude and significance of these variations. Future public health research can determine whether these temporal and quantitative pollen changes correlate with longitudinal differences in population pollen sensitization.
花粉起始时间、持续时间和强度的纵向变化是越来越多花粉致敏个体的公共卫生关注点。对长期花粉变化的国家分析受到如何定义植物主要花粉季节 (MPS) 的影响。先前的瑞士研究对 MPS 定义的应用不一致，导致关于数十年来花粉趋势的幅度、方向性和显著性的结论不一致。我们研究了瑞士 1990 年至 2020 年期间的全国花粉数据，对 12 种相关致敏植物应用了六种 MPS 定义（两种基于百分比和四种基于阈值）。我们使用线性回归和局部估计散点平滑（LOESS）分析花粉季节的变化。对于 12 种植物中的 4 种，在花粉季节开始时间更早（p < 0.05）方面，各种定义之间存在一致性，31 年变化幅度取决于特定的 MPS 定义（榛树：9-18 天；橡树：5-13 天；草类：8-25 天；荨麻/大麻：6-25 天）。榛树（21-104%更长）、荨麻/大麻（8-52%更长）和白蜡（18-38%更短）的 MPS 持续时间也存在共识（p < 0.05）。在 MPS 强度分析中，不同定义之间的一致性最高，榛树、桦树、橡树、山毛榉和荨麻/大麻的季节性花粉数量显著增加（p < 0.05）。榛树（110-146%）和山毛榉（162-237%）的相对强化最为显著。LOESS 分析表明，这些数十年的花粉变化通常是非线性的。MPS 定义的稳健性高度依赖于年度花粉积累，定义选择对豚草等低花粉植物的长期分析尤其有影响。我们发现 MPS 定义之间存在系统差异，并建议未来的空气生物学研究应用多种定义以最大程度地减少偏差。总之，瑞士一些植物的全国花粉起始时间、持续时间和强度发生了变化，MPS 定义的选择影响这些变化的幅度和显著性。未来的公共卫生研究可以确定这些时间和数量花粉变化是否与人群花粉致敏的纵向差异相关。
