The influence of HT and obesity on AR has been extensively discussed [20]. A better understanding of how HT and BMI impact AR could aid in managing rhinitis symptoms in perimenopausal patients and thereby considerably reduce the social and economic burden of the disease. The perimenopause is an important period in the life course of women. Instability of the hypothalamic-pituitary ovarian axis (HPO) in perimenopausal women leads to fluctuations in sex hormone levels, various discomfort symptoms, as well as endocrine disorders, disorders of glucose and lipid metabolism, hypertension, and heart disease [21, 22]. All of these disorders prompt perimenopausal women to seek medical attention and professional hormone therapy to relieve their symptoms.

The present study enrolled 950 women aged 45–55 years, of which 393 (41.3%) were using HT at the time of the study. HT is a potent treatment for menopausal symptoms and has been previously used to reduce coronary heart disease (CHD) and mortality [23]. However, HT can cause side effects such as breast tenderness, mood changes, and uterine bleeding. Of particular concern, HT increases the risks for cancer and venous thromboembolism [24, 25]. Recent studies have found that HT increases the risk for asthma and asthma symptoms in women. However, rarely studies have reported the effects of HR on perimenopausal women, and especially its effects on body mass index. In our study, women who used HT had a lower body mass index, more menopausal symptoms, a lower rate of hypertension, higher rates of heart disease, type 2 diabetes, and hyperlipidemia, but a lower prevalence of hypertension. These results are similar to those in previous studies [26]. However, the effects of hormone therapy on blood pressure are controversial [27, 28]. In our study, there was a significant reduction in the incidence of hypertension among perimenopausal women receiving HT, which we considered to be related to hormone therapy improving the biological effects of nitric oxide (NO) and reducing the effects of angiotensin II, thereby causing vasodilation and leading to a decrease in blood pressure [29].

Several studies have shown that sex hormones are associated with rhinitis [30]. Female sex hormone receptors expressed by nasal epithelial cells are correlated with the severity of rhinitis symptoms [31]. The use of oral hormones was found to induce inter-epithelial edema and histiocytic proliferation in human nasal mucosa [32]. Furthermore, circumstantial evidence for the effect of female sex hormones on rhinitis suggests that the menstrual cycle and pregnancy can cause rhinitis symptoms [33]. In this study, the prevalence of AR was significantly higher among HT users. However, the relationship between the two was independent of age at menarche, number of pregnancies, and age at menopause. HT not only causes AR and asthma, but also impairs the immune system and leads to other allergic symptoms. In our research, we found that perimenopausal women who used HT had more asthma, more accompanying symptoms, and more often developed food and drug reactions. When taken together, these results indicated that the duration of endogenous estrogen exposure was not associated with nasal mucosal sensitization status in premenopausal women treated with HT, but might be associated with systemic allergen sensitization status [34, 35].

Obesity exacerbates HT-induced inflammation, activates inflammatory cells, and thereby contributes to the severity of AR [18, 36, 37]. This study showed that the proinflammatory effect of IR in high BMI may be the cause of AR, that is, the direct effect of HT on AR appears to be offset by the improvement in IR-dependent AR in obese women. The risks for AR and relevant symptoms related to HT use were significantly greater in lean women than in normal weight and heavier women. The possible mechanism for this finding is that in lean women, HT exerts a direct pro-inflammatory effect on the organism and thus contributes to the development of AR, compared with lower levels of insulin resistance. However, in heavier women, this effect may be counteracted by a reduction in HT-related IR. Obesity leads to insulin resistance (IR) and inflammation [38, 39], and previous studies suggest that the association between AR and BMI may be due to the proinflammatory effects of IR [40, 41]. The same mechanism has been described for breast cancer, where the risk for breast cancer among HT users was greater in lean women [42, 43], suggesting a complex interplay between sex hormones, fatty tissue, and metabolism.

This is the first clinical study to examine the connection between HT and AR and investigate the relationship between obesity and AR in perimenopausal women. At the same time, this is the first study to look at the interaction between HT and obesity in AR. However, our study does have some limitations. First, we examined age, education, and occupation as potential confounders, but did not examine numerous other variables such as smoking history and living environment (rural or urban). Further studies with large samples sizes should be conducted to investigate the effect of additional related variables in the future. Second, the specific mechanisms of interactions among HT, AR, and BMI were not thoroughly investigated. Additional studies with large sample sizes will be needed to explore the mechanism of interaction between HT and AR. Third, we did not know what type of HT was used or when it was used by the patients. Therefore, we were unable to know the order of AR and HT, and the effect of specific drugs on the disease. However, in some previous studies, investigators did not observe a difference between the effects of various hormones on lower airway anaphylaxis [44]. Although the causes and underlying mechanisms of HT and AR require further exploration, this is the first study to evaluate the relationships between HT, BMI, and AR prevalence in perimenopausal women.