Menopause is an important process in women’s lives. It is characterized by the loss of ovarian activity and permanent cessation of menses and diagnosed after 12 consecutive months of amenorrhea [1]. Estrogen is known to promote vasodilation and lower blood pressure (BP) [2], and thus, loss of estrogen during menopause is considered to drive the development of hypertension in postmenopausal women. Scuteri et al. have reported that postmenopausal women who received hormone replacement therapy had a lower systolic BP increase than non-users over a 10-year follow-up period [3]. Estrogen therapy is recommended in patients with hypertension. Moreover, among postmenopausal women, age at menopause has been reported to be inversely associated with BP and the risk of hypertension [4, 5].

However, several studies have demonstrated a positive association between age at menopause and hypertension [6,7,8]. Additionally, a positive association between age at menopause and obesity has been reported [9, 10]. In the Japanese Nurse’s Health Study, a positive association between age at menopause and hypertension was described; however, the association disappeared after adjusting for body mass index (BMI) [7]. Shen et al. have also reported that the age at menopause was positively associated with hypertension mediated by BMI [6]. Thus, late age at menopause may be associated with higher BP mediated by obesity; however, this presumption remains to be elucidated.

In this issue of Hypertension Research, Wu et al. [11] reported data investigating the mediation effects of obesity indicators, including BMI, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR), on the association between age at menopause and BP in 5,429 natural postmenopausal women in a Chinese cohort study. In this study, a non-linear (U-shape-like) association was observed between age at menopause and hypertension with a nadir of 50 years. No significant association between age at menopause and BP was observed in 1,722 women aged < 50 years. By contrast, among 3,707 women with a menopausal age of ≥50 years, significant and positive associations were observed between age at menopause and systolic or diastolic BP, which were mediated by BMI, WC, WHR, and WHtR.

These data are interesting because they were generally consistent with those of previous studies indicating that late age at menopause was associated with higher risks of obesity and elevated BP and have added to the literature by estimating the proportion of mediation through obesity indicators.

The mechanism by which late age at menopause is associated with higher BP mediated by obesity remains unclear. However, prolonged estrogen exposure may play a key role in this phenomenon (Fig. 1). Estrogen reportedly causes accumulation of adipose tissues [12]. Additionally, adiposity has been considered a mediator in the association between earlier age at menarche and a higher prevalence of hypertension [13, 14]. Therefore, prolonged estrogen exposure may induce obesity and hypertension. However, neither obesity indicators nor BP data at the time of menopause were included in this study. The loss of estrogen with menopause shifts adipose tissue accumulation away from the lower body towards central/abdominal deposition [15]. Furthermore, the association between estrogen and adiposity may be bidirectional [16]. Therefore, causal relationships cannot be estimated in a cross-sectional study, as in this study. Longitudinal studies on obesity indicators and BP before and after the onset of menopause should be conducted in the future.

Fig. 1
figure 1

Proposed mechanism of blood pressure elevation in women with early menarche and those with late menopause. In women with early menarche and those with late menopause, prolonged exposure to estrogen may induce obesity, causing elevated blood pressure after menopause. BP blood pressure

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In conclusion, this study reveals a significant finding that maintaining a healthy body weight may be beneficial in preventing BP elevation after menopause, especially in women experiencing menopause at a late age. Further studies focusing on the associations between age at menopause and metabolic factors such as obesity, glycolipid metabolism, and BP are warranted.