年齢特有の生育傾向が全体的な生育傾向に及ぼす影響:米国,1990-2023年
まとめ
アメリカでの生育率の低下は 主に30歳未満の女性の出生率の低下に起因しています 年配の女性の出生率の減少にも関わらずです この人口変化が 総出生数と生育率に 影響を及ぼします
科学分野:
- 人口統計
- 公衆衛生
- 社会学
背景:
- 生殖率は人口動態と社会動向の重要な指標です.
- 近年では 異なる年齢層における 母親の年齢分布と出生率が変化しています
- 年齢特有の生育傾向を理解することは,出生率の全体的な変化を解釈する鍵です.
研究 の 目的:
- アメリカにおける出生率の減少に対する年齢特有の出生率の傾向の影響を分析する.
- 1990年から2023年にかけての一般生育率 (GFR) と総生育率 (TFR) の変化に対する異なる母年齢層の寄与を定量化する.
主な方法:
- 1990年から2023年までの米国国立生命統計システムの出生データを活用した.
- 1990年の年齢特有の生育率を,その後の数年間一定に保って,率の変化の影響を隔離するために,シミュレーション方法を用いた.
- 実際の観測傾向と比較するために調整された出生数,GFR,TFRを計算した.
主要な成果:
- 1990年から2023年の間に米国の出生率は14%,GFRは23%,TFRは22%減少した.
- 30歳未満の女性の出生率の低下は,全体的な生育率の減少に大きく寄与しました.
- 30歳以上の女性の出生率の上昇は,減少を部分的に相殺したが,傾向を逆転させるには十分ではなかった.
結論:
- 米国における出生率の全体的な低下は,主に若い女性 (30歳未満) の出生率の低下によるものです.
- 母親の年齢分布の変化は 若い女性の出産が減少し 年配の女性の出産が増加していることを示しています
- アメリカにおける出生率や 総産率の変化の主な要因は 年齢特有の出生傾向です
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