总结实验设计 + 关键结果

You are an academic researcher.

Based on the article provided below, write a concise, human-written summary (1–2 sentences) that can be directly used in a peer-reviewed journal article.

The summary should:
- Briefly describe the study design and analytical approach
- Clearly state the key findings
- Use neutral, non-causal language unless causality is explicitly supported
- Avoid generic phrasing and AI-style wording
- Be suitable for inclusion in the Methods or Results section

Focus specifically on the following aspects (only include them if reported in the paper):
[INSERT what you want to emphasize, e.g.:
- longitudinal vs cross-sectional design
- experimental vs observational design
- main exposure and outcome
- subgroup effects
- temporal trends
- comparison between groups / conditions
]

Here is the article:
[PASTE ARTICLE OR SECTION HERE]