A Prospective Study of Factors Affecting Age at Menopause among the Bandar-E-Kong Cohort

Research Article

A Prospective Study of Factors Affecting Age at Menopause among the Bandar-E-Kong Cohort

Roozbeh N¹, Masoudi M², Moannaie M³, Nejatizadeh A4 and Kutenaee MA³*

1Mother and Child Welfare Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran

2Fatemiyeh Shiraz Institute of Higher Education, Shiraz, Iran

3Department of Gynecology and Obstetrics, School of Medicine, Fertility and Infertility Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran

4Molecular Medicine Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran

*Corresponding author: Maryam Azizi Kutenaee, Department of Gynecology and Obstetrics, School of Medicine, Fertility and Infertility Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran

Received: September 27, 2021; Accepted: October 26, 2021; Published: November 02, 2021

Abstract

Menopause is a natural period of women’s life and can be affected by several factors. This paper describes and identify the age of natural menopause and its associated factors based cohort study in Iran. In this study, we used data of Bandar-e-Kong study. This prospective cohort study includes 2,334 woman’s aged between 18 to 70 years old, which was conducted from March 2016 to February 2019. All women completed data collection forms includes a validated questionnaire survey. Data were analyzed using chi-square test, independent t test, and ANOVA as well as a multivariate linear regression model. The total of participants with the age range of 18-70 years, 894 were menopause females. The mean age of menopause was 48.31 ± 6.34 years with a minimum of 20 and a maximum of 66 years. The number of pregnancies, duration of breastfeeding, level of education, residency, presence of thyroid disease, and body mass index affected the age of menopause. This study suggests that number of pregnancy was associated with menopausal age. According to the results of this study, the existence of appropriate educational programs to promote awareness and lifestyle in postmenopausal women is essential.

Keywords: Menopause; Menopausal age; Bandar-e- Kong Cohort Study; Healthcare policy

Introduction

Menopause is defined as a loss of menstruation for women and lead to transition process from reproductive to a non-reproductive state by ovarian failure in all women. Estrogen levels decrease and eventually lead to the menstrual cessation. This natural biological process usually occurs between 45 and 55 years [1]. Previous studies have reported that menopause can lead to influence on normal function of immune, cardiovascular, skeletal endocrine and genitourinary systems and will result in various diseases, such as high blood cholesterol, cardiovascular disease, osteoporosis, bone fractures and even Alzheimer’s [2-5]. Based on WHO report by the year 2030, approximately 1.2 billion women of global population entered menopause and 47 million will be added every year [4]. One of the most important issues associated with menopause is early menopause. Early menopause is related to the decrease of hormonal secretion and ovarian estrogen deficiency over time [3]. Premature or early menopause can be characterized by several signs like as last menstruation between 40 to 44 years old, to consider that the median age of natural menopause is age 51 years [6]. Hyvärinen, Karvanen [5] reported that, common menopausal symptoms is including; joint pain, hot flushes, night sweats, headache, urinary tract and vaginal problems, osteoporosis, irritability or increased anxiety, pain during intercourse, cardiovascular diseases and finally amenorrhea and lack of estrogen [3]. Menopausal age varies in different geographical areas according to environmental and socio-economic variables, lifestyle and quality also, contraceptive pills, menarche age, calcium and vitamin D intake, genetic factors, diet, alcohol, obesity can be affected on it [2,4,7,8]. In studies about age at natural menopause, it is necessary to pay attention to the physical, behavioral characteristics and sociodemographic [5,9-12]. The average age of menopause is 51 years for US women [13]. For the majority of enrolled women in Europe the median age of natural menopause is 48 to 54 years [12,14,15], also, the age at menopause for Asian women reported 49 to 51 [16-20]. Several author’s [16,21-23] have been reported the mean age at menopause 46.9 to 49.6 years for Iranian women in different part of Iran. One third of women’s life spends in the postmenopausal period, it is useful to increase knowledge about the risk factors for onset of menopause across populations. One particular region where studies of menopause onset have been sparse is south of Iran. In the present large-scale population based cohort study we explore the relationship between ages of natural menopause with main associated factors in women who lived in south of Iran.

Materials and Methods

Patients and study design

We evaluated participants of the Bandar-e- Kong Cohort Study (KCS), KCS is part of the national cohort, a prospective, populationbased cohort study in Iran, which has been previously described in detail [24]. This prospective cohort study includes 2,334 woman’s aged between 18 to 70 years old, which was conducted from March 2016 to February 2019. All women completed data collection forms includes a validated questionnaire survey. All study procedures were approved by the Ethics Committee of the Hormozgan University of Medical Sciences (IR.HUMS.REC.1399.494).

Of 2,334 women who responded, decided to continue, and consented, 1440 were excluded based on the exclusion criteria. These criteria included several factors and medical conditions that could affect the timing of the final menstrual period or hinder the menopausal group definitions, such as severe obesity (body mass index more than 35), bilateral oophorectomy, women with surgical menopause (hysterectomy), polycystic ovary syndrome, pregnancy and use of estrogen containing medications.

Finally, the sample of 894 women participate to this study. A validated research database was used containing questions consist of general information, physical activity, physical examination, physical disabilities, sleep status, oral health, drug use, familial history of diseases, type of fuel used, life style, history of chronic diseases, occupational history, characteristics of the habitat, socioeconomic status, personal habits (drinking and smoking), food supplements, food frequency, exposure to pesticides, water drink, dietary habits and history of fertility. To describe the reproductive section of the questionnaire in more details, we got some information about the age at menarche, number of pregnancy, number of abortion, breastfeeding duration (month), age of the first marriage (y). Also to explain the socioeconomic status of the questionnaire in more details, we asked women about the travelling (internal trip or abroad trip), reading the books, access to computer and internet, owning a car/motorcycle, household appliances such as washing machine, dishwasher, vacuum cleaner and freezer. All the variables mentioned are numbered and based on total number of the whole socio-economic status categorized in five levels; level 1, poorest, level 2, Poor, level 3, moderate, level 4, good and level 5 richest.

Anthropometric indices and blood pressure were measured for all participants. Based on PERSIAN protocol all anthropometric indices include height and weight and waist and hip circumferences were measured by trained nurses [25]. All data were analyzed by using IBM SPSS-23.0 (IBM Corp., Armonk, NY, USA). Variables were described using maximum, minimum, mean, standard deviation and percentage. Quantitative variable and categories were compared in to groups using chi-square and independent t test respectively. ANOVA was used to compare quantitative variables in more than two groups. For possible confounding variables, we used the multivariate linear regression models. Variables with P value less than 0.2 were considered in model, which include marital status, number of pregnancy, breastfeeding duration, educational level, BMI and residency thyroid diseases (participant who self-reported to clinically diagnosed with thyroid disease or receiving thyroid related medicine). A written informed consent form was obtained from all participants before inclusion in the evaluation.

Results

In this present we notice to women who menopause naturally and follow the analysis on its related factors, although we look at data for premature and early menopause. The total of participants with the age range of 18-70 years, 894 were menopause females. The mean age of menopause was 48.31 ± 6.34 years with a minimum of 20 and a maximum of 66 years. The prevalence of premature menopause, early menopause and normal menopause was 79 (8.8%), 116 (13.0%) and 699 (78.2%), respectively. The mean age of premature, early and natural menopause was 34.27 ± 3.52, 42.00 ± 1.55 and 50.95 ± 3.71, respectively (P < 0.001). Table1 shows characteristic of participants included age of menarche, number of pregnancy, number of abortion, breastfeeding and duration, age of the first marriage and its association with menopause age. By using ANOVA test, compared the mean age of menopause in different socio-economic levels. The mean age of menopause was 48.86 ± 6.13 for lowest and 48.30 ± 6.250 for highest socio-economic level (P = 0.105). The mean age of menopause in women with and without history of infertility was 46.56 ± 9.514 vs. 48.45 ± 6.114; P = 0.051 respectively. Moreover there was no significant difference between the mean age of menopause in women with different marital status (single, married and widow/ divorced), (48.50 ± 5.663, 48.39 ± 6.205, 47.93 ± 7.080, P = 0.722).

The result of correlation coefficient between menopausal age with abortion, breastfeeding duration and age at the first pregnancy, number of pregnancies, age at the first marriage, and age of menarche was calculated in Table 4. Based on Table 4, by adjusting the effect of other variables, for one unit of increase in the number of pregnancies, the mean of menopause age almost increased by 0.2 (P-value = 0.074). The mean menopause age was 0.92 less for people with the highest socio-economic status than the poor ones (P-value = 0.054). Also, for women with premature menopause, the mean menopause age for people with a history of infertility was 2.55 less than their counterparts (P-value = 0.092). Moreover, by controlling the effect of other variables, for women with normal menopause, the mean menopause age for women with a history of infertility was 1.36 less than their counterparts (P-value = 0.091) and menopause age was 0.89 less for people with the highest socio-economic status than the poor ones (P-value = 0.006).

The average age of the menarche, number of pregnancies, number of abortions, duration of breastfeeding, and the age at the first marriage of participants are presented in Table 1. The correlation coefficient between variations that summarized in Table 1 was calculated, with increasing the number of pregnancy the age of menopause in premature menopause and normal menopause significantly increased (P < 0.001). The frequency of variable such as stillbirth, tubectomy, infertility, diabetes, hypertension, thyroid disease, cardiac disease and cardiovascular disease (CVD) are showed in Table 2. By information that presented in Table 2, as shown in that, it is most frequency among people with a history of hypertension and low frequency belong to infertility group.

Table 1: Characteristic of study participants and its association with menopause age.










  


    
Variable 


    
Total (n=894)


    
Premature Menopause (n=79)


    
Early Menopause


      (n=116)


    
Normal Menopause


      (n=699)


    
P-value*


  


  


    
Mean ± SD


    
Correlation (P value)


    
Mean ± SD


    
Correlation (P value)


    
Mean ± SD


    
Correlation (P value)


    
Mean ± SD


    
Correlation (P value)


  


  


    
Age of menarche (y)


    
13.75±1.530


    
0.049


      0.143


    
13.71±1.46


    
0.187


      0.102


    
13.51±1.42


    
0.11


      0.24


    
13.80±1.55


    
0.002


      0.953


    
0.165


  


  


    
Number of pregnancy


    
6.80±3.021


    
0.142


      <0.001


    
6.19±3.035


    
0.405


      <0.001


    
6.41±2.803


    
-0.085


      0.369


    
6.93±3.04


    
0.12


      0.002


    
0.045


  


  


    
Number of abortion


    
0.63±1.011


    
0.064


      0.061


    
0.61±1.170


    
0.112


      0.351


    
0.52±0.763


    
-0.103


      0.284


    
0.65±1.02


    
0.074


      0.054


    
0.423


  


  


    
Breastfeeding duration (mo)


    
107.96±64.71


    
0.077


      0.024


    
100.63±59.74


    
0.236


      0.046


    
112.35±61.17


    
0.049


      0.612


    
108.03±65.79


    
0.113


      0.003


    
0.489


  


  


    
Age of the first marriage (y)


    
18.41±4.712


    
-0.054


      0.112


    
18.61±5.73


    
-0.248


      0.028


    
18.68±4.72


    
0.056


      0.564


    
18.34±4.58


    
-0.046


      0.231


    
0.728


  


  


    
*P-value for ANOVA to compare mean of premature    age, early age and natural menopause age 


  


















Table 1: Characteristic of study participants and its association with menopause age.

Table 2: Frequency of categorical variables in three menopausal groups.










  


    
Variable


    
Total    (n=894)


    
Premature    Menopause Age (n=79)


    
Early    Menopause Age (n=116)


    
Normal    Menopause Age (n=699)


  


  


    
Number


    
Percent


    
Number


    
Percent


    
Number


    
Percent


    
Number


    
Percent


  


  


    
Stillbirth


    
170


    
19


    
22


    
27.8


    
16


    
13.8


    
132


    
18.9


  


  


    
Tubectomy


    
265


    
29.6


    
22


    
27.8


    
28


    
24.1


    
215


    
30.8


  


  


    
Infertility


    
45


    
5


    
8


    
10.1


    
5


    
4.3


    
32


    
4.6


  


  


    
Diabetes


    
219


    
24.5


    
19


    
24.1


    
30


    
25.9


    
170


    
24.3


  


  


    
Hypertension


    
301


    
33.7


    
23


    
29.1


    
39


    
33.6


    
239


    
34.2


  


  


    
Thyroid Disease


    
126


    
14.1


    
15


    
19


    
16


    
13.8


    
95


    
13.6


  


  


    
Cardiac Disease


    
135


    
15.1


    
9


    
11.4


    
22


    
19


    
104


    
14.9


  


  


    
CVD history


    
147


    
16.4


    
9


    
11.4


    
24


    
20.7


    
114


    
16.3


  


















Table 2: Frequency of categorical variables in three menopausal groups.

Mean of menopause age based on marital status, socio-economic status, job, thyroid disease, diabetes, hypertension, cardiac disease, CVD history, body mass index, smoking, still birth, infertility and Tubectomy showed in Table 3. We compared the age of menopause in women with and without diabetes. Our results showed that the age of menopause in premature menopause age group with diabetes is significantly higher than women without diabetes (35.68 ± 2.92 vs. 33.82 ± 3.06; P = 0.043). Also, we found that the age of menopause in premature menopause age group with infertility is significantly lower than women without infertility (29.13 ± 5.22 vs. 34.84 ± 2.826; P < 0.001). On the other hand, the age of menopause in normal menopause age group with tubectomy is significantly higher than women without Tubectomy (34.84 ± 2.82 vs. 29.13 ± 5.22; P < 0.001). Association of natural menopausal age with selected variables using multivariate linear regression of participants are summarized in Table 4. Multivariable regression analysis showed that menopause age was 0.89 less for people with the highest socio-economic status than the poor ones (P-value = 0.006) Table 4.

Table 3: Mean of menopause age based on categorical variables.










  


    
Variable


    
Total    (n=894)


    
premature    menopause age (n=79)


    
early    menopause age


      (n=116)


    
normal    menopause age


      (n=699)


    
P value*


  


  


    
Mean ±    SD


    
P value


    
Mean ±    SD


    
P value


    
Mean ±    SD


    
P value


    
Mean ±    SD


    
P value


  


  


    
Marital status


    
Single


    
48.50±5.663


    
0.722


    
34.10±3.198


    
0.639


    
41.71±1.496


    
0.701


    
51.67±3.658


    
0.423


    
<0.001


  


  


    
Married


    
48.39±6.205


    
34.16±3.189


    
42.07±1.545


    
50.87±3.640


    
<0.001


  


  


    
Widow/Divorce


    
47.93±7.080


    
34.61±4.578


    
41.81±1.662


    
51.28±4.055


    
<0.001


  


  


    
Soci-economic status


    
Poorest


    
48.86±6.13


    
0.105


    
34.80±3.688


    
<0.001


    
42.14±1.711


    
<0.001


    
51.5±3.860


    
<0.001


    
<0.001


  


  


    
Poor


    
48.91±6.765


    
33.67±4.451


    
42.00±1.451


    
51.69±3.728


    
<0.001


  


  


    
Moderate


    
48.19±6.250


    
34.40±2.746


    
41.70±1.589


    
50.96±3.600


    
<0.001


  


  


    
Rich


    
47.34±6.212


    
34.71±3.327


    
42.15±1.523


    
50.38±3.580


    
<0.001


  


  


    
Richest


    
48.30±6.250


    
33.46±4.701


    
42.00±1.604


    
50.55±3.604


    
<0.001


  


  


    
Job


    
No


    
48.37±6.405


    
0.516


    
34.20±3.624


    
0.68


    
41.92±1.548


    
0.167


    
51.03±3.721


    
0.132


    
<0.001


  


  


    
Yes


    
47.96±5.916


    
34.70±2.869


    
42.50±1.549


    
50.40±3.585


    
<0.001


  


  


    
Thyroid disease


    
No


    
48.43±6.329


    
0.161


    
34.22±3.369


    
0.808


    
41.95±1.533


    
0.389


    
51.01±3.780


    
0.243


    
<0.001


  


  


    
Yes


    
47.58±6.394


    
34.47±4.257


    
42.31±1.702


    
50.54±3.195


    
<0.001


  


  


    
Diabetes


    
No


    
48.27±6.429


    
0.684


    
33.82±3.061


    
0.043


    
41.95±1.571


    
0.588


    
50.93±3.685


    
0.803


    
<0.001


  


  


    
Yes


    
48.47±6.078


    
35.68±2.926


    
42.13±1.525


    
51.01±3.787


    
<0.001


  


  


    
Cardiac Disease


    
No


    
48.30±6.343


    
0.83


    
34.37±3.564


    
0.461


    
41.99±1.548


    
0.88


    
50.93±3.662


    
0.727


    
<0.001


  


  


    
Yes


    
48.42±6.355


    
33.44±3.283


    
42.05±1.618


    
51.07±3.976


    
<0.001


  


  


    
CVD history


    
No


    
48.28±6.374


    
0.724


    
34.37±3.564


    
0.461


    
41.97±1.551


    
0.66


    
50.94±3.671


    
0.853


    
<0.001


  


  


    
Yes


    
48.48±6.195


    
33.44±3.283


    
42.13±1.597


    
51.01±3.907


    
<0.001


  


  


    
Body mass index (kg/m2)


    
< 25


    
48.47±6.835


    
0.707


    
34.41±3.885


    
0.641


    
42.35±1.450


    
0.186


    
51.41±4.006


    
0.11


    
<0.001


  


  


    
25–30


    
48.40±6.017


    
34.61±2.514


    
42.02±1.581


    
50.86±3.662


    
<0.001


  


  


    
> 30


    
48.05±6.313


    
33.71±4.144


    
41.65±1.574


    
50.67±3.460


    
<0.001


  


  


    
Smoking


    
No


    
48.28±6.305


    
0.696


    
33.97±3.571


    
0.108


    
42.04±1.549


    
0.479


    
50.91±3.616


    
0.469


    
<0.001


  


  


    
Yes


    
48.51±6.583


    
35.61±3.054


    
41.73±1.624


    
51.19±4.211


    
<0.001


  


  


    
Stillbirth


    
No


    
48.49±5.899


    
0.801


    
34.98±2.810


    
0.298


    
42.05±1.575


    
0.48


    
50.85±3.645


    
0.067


    
<0.001


  


  


    
Yes


    
48.36±7.205


    
34.23±2.793


    
41.75±1.612


    
51.52±4.063


    
<0.001


  


  


    
Infertility


    
No


    
48.45±6.114


    
0.051


    
34.84±2.826


    
<0.001


    
42.00±1.581


    
1


    
50.94±3.712


    
0.306


    
<0.001


  


  


    
Yes


    
46.56±9.514


    
29.13±5.222


    
42.00±1.225


    
51.61±3.722


    
<0.001


  


  


    
Tubectomy


    
No


    
48.31±6.600


    
0.948


    
33.82±3.616


    
0.073


    
42.02±1.576


    
0.782


    
51.15±3.822


    
0.03


    
<0.001


  


  


    
Yes


    
48.34±5.695


    
35.41±3.065


    
41.93±1.514


    
50.49±3.401


    
<0.001


  


  


    
*P-value for ANOVA to    compare mean of premature age, early age and natural menopause age 


  


















Table 3: Mean of menopause age based on categorical variables.

Table 4: The effect of selected variables on menopause age using multivariate linear regression.










  


    
Variable


    
Total    (n=894)


    
premature menopause age (n=79) 


    
early    menopause age


      (n=116)


    
normal    menopause age


      (n=699)


  


  


    
Unstandardized    Beta


    
standardized    Beta


    
*P    value


    
Unstandardized    Beta


    
standardized    Beta


    
P value


    
Unstandardized    Beta


    
standardized    Beta


    
P value


    
Unstandardized    Beta


    
standardized    Beta


    
P value


  


  


    
age of menarche


    
0.093


    
0.023


    
0.508


    
0.194


    
0.103


    
0.414


    
0.182


    
0.159


    
0.119


    
-0.039


    
-0.016


    
0.676


  


  


    
Number of pregnancies


    
0.198


    
0.091


    
0.074


    
0.028


    
0.026


    
0.882


    
-0.128


    
-0.208


    
0.162


    
0.066


    
0.051


    
0.374


  


  


    
number of abortion


    
0.142


    
0.023


    
0.564


    
0.312


    
0.13


    
0.352


    
-0.162


    
-0.078


    
0.485


    
0.175


    
0.048


    
0.291


  


  


    
breastfeeding duration


    
0.001


    
0.007


    
0.871


    
0.011


    
0.231


    
0.17


    
0.002


    
0.09


    
0.507


    
0.004


    
0.068


    
0.176


  


  


    
Age of the first marriage


    
-0.003


    
-0.002


    
0.956


    
0.006


    
0.009


    
0.942


    
0.031


    
0.091


    
0.404


    
-0.019


    
-0.023


    
0.555


  


  


    
Infertility


    
No


    
Reference


  


  


    
Yes


    
-0.153


    
-0.005


    
0.894


    
-2.55


    
-0.25


    
0.092


    
-0.255


    
-0.031


    
0.772


    
-1.361


    
0.065


    
0.091


  


  


    
Socio-economic status


    
Poor


    
Reference


  


  


    
Moderate


    
-0.687


    
-0.044


    
0.24


    
0.512


    
0.071


    
0.613


    
0.021


    
0.006


    
0.961


    
-0.444


    
0.047


    
0.267


  


  


    
Rich


    
-0.926


    
-0.073


    
0.054


    
0.04


    
0.007


    
0.957


    
0.04


    
0.012


    
0.914


    
-0.895


    
-0.117


    
0.006


  


  


    
* With a 90 percent level of confidence 


  


















Table 4: The effect of selected variables on menopause age using multivariate linear regression.

Discussion

This paper is modest contribution to the ongoing discussions about factors affecting age at menopause among the Bandar-e-Kong cohort in south of Iran. In our study, mean age of menopause in total population was 48.31 ± 6.34 with a minimum of 20 and a maximum of 66 years. In Overall our findings about mean of menopause is similar to the other studies in Iran [16,26-31]. Although the mean age of natural menopause in Bandar-e-Kong cohort population is lower than Hamedan province (49.6 ± 4.0) [32]. In compare to other countries, age of menopause in our finding was less than western countries [33-35], but it is higher than Chines women (50.53 ± 6.57) and Panjabi women (47.9 ± 3.2) [36,37]. In many study noticed to genetic and environmental factors that affected on the age of menopause [38]. We found that number of pregnancy as one of the important reproductive variable is related to age of menopause. Age at monarch is one of the important factors to age at menopause [39], based our results we did not find any association with this factor to age at menopause. Association between age at monarch and menopausal age was inconsistent in previous studies [27]. In this study we did not find any association between marital status and menopausal age. This Association has not been reported consistently in previous studies. Unlike the previous studies, results of present study did not show any significant relationship between BMI and menopausal age. Some studies reported that no association between BMI and age of menopause [36]. In our plan study we compared age at menopause in women with and without some diseases. Among of listed disease in Table 3, diabetes was significantly related with menopausal age but hypertension and thyroid were not related with age at menopause. Cigarette smoking can lead to perimenopause and reached the menopause early than non-smokers [40]. In this study the number of smoker was low, so we find no association between smoking and menopausal age. Like the previous studies [13,41,42], our result showed that significant relationship between socio-economic level and menopausal age. Some limitation of the present study should be considered that, reproductive history of women was self-reported of events years back in their life which can be subject to recall bias, and moreover remembering the exact time of menopause might be subject to recall bias as well.

In conclusion, the study suggests that number of pregnancy was associated with menopausal age. According to the results of this study, the existence of appropriate educational programs to promote awareness and lifestyle in postmenopausal women is essential.

References

  1. Who S. Research on the Menopause in the 1990’s: A Report of the WHO Scientific Group. Geneva: World Health Organization. 1996: 1-107.
  2. Honour JW. Biochemistry of the menopause. Annals of clinical biochemistry. 2018; 55: 18-33.
  3. Gallagher JC. Effect of early menopause on bone mineral density and fractures. Menopause. 2007; 14: 567-571.
  4. Nackers LM, Appelhans BM, Segawa E, Janssen I, Dugan SA, Kravitz HM. Associations between body mass index and sexual functioning in midlife women: The Study of Women’s Health across the Nation (SWAN). Menopause (New York, NY). 2015; 22: 1175-1181.
  5. Hyvärinen M, Karvanen J, Aukee P, Tammelin TH, Sipilä S, Kujala UM, et al. Predicting the age at natural menopause in middle-aged women. Menopause: the Journal of the North American Menopause Society. 2021; 28: 792-799.
  6. Shuster LT, Rhodes DJ, Gostout BS, Grossardt BR, Rocca WA. Premature menopause or early menopause: long-term health consequences. Maturitas. 2010; 65: 161-166.
  7. Tan MN, Kartal M, Guldal D. The effect of physical activity and body mass index on menopausal symptoms in Turkish women: a cross-sectional study in primary care. BMC women’s health. 2014; 14: 38.
  8. Purdue-Smithe AC, Whitcomb BW, Szegda KL, Boutot ME, Manson JE, Hankinson SE, et al. Vitamin D and calcium intake and risk of early menopause. The American journal of clinical nutrition. 2017; 105: 1493-1501.
  9. Huan L, Deng X, He M, Chen S, Niu W. Meta-analysis: Early Age at Natural Menopause and Risk for All-Cause and Cardiovascular Mortality. BioMed research international. 2021; 2021.
  10. Li H, Hart JE, Mahalingaiah S, Nethery RC, Bertone-Johnson E, Laden F. Long-term exposure to particulate matter and roadway proximity with age at natural menopause in the Nurses’ Health Study II Cohort. Environmental Pollution. 2021; 269: 116216.
  11. Reynolds R, Obermeyer C. Age at natural menopause in Beirut, Lebanon: the role of reproductive and lifestyle factors. Annals of human biology. 2001; 28: 21-29.
  12. Koukouliata A, Nena E, Koutlaki N, Liberis V, Constantinidis T. Correlation of age at natural menopause with occupational status and other epidemiologic factors in women from Prefecture of Kavala, Greece. Hippokratia. 2017; 21: 32-37.
  13. Schoenaker DA, Jackson CA, Rowlands JV, Mishra GD. Socioeconomic position, lifestyle factors and age at natural menopause: a systematic review and meta-analyses of studies across six continents. International journal of epidemiology. 2014; 43: 1542-1562.
  14. Stepaniak U, Szafraniec K, Kubinova R, Malyutina S, Peasey A, Pikhart H, et al. Age at natural menopause in three central and eastern European urban populations: the HAPIEE study. Maturitas. 2013; 75: 87-93.
  15. Dratva J, Real FG, Schindler C, Ackermann-Liebrich U, Gerbase MW, Probst- Hensch NM, et al. Is age at menopause increasing across Europe? Results on age at menopause and determinants from two population-based studies. Menopause. 2009; 16: 385-394.
  16. Golshiri P, Akbari M, Abdollahzadeh MR. Age at natural menopause and related factors in Isfahan, Iran. Journal of menopausal medicine. 2016; 22: 87.
  17. Ilankoon IMPS, Samarasinghe K, Elgán C. Menopause is a natural stage of aging: a qualitative study. BMC women’s health. 2021; 21: 1-9.
  18. Ishak NNM, Jamani NA, Arifin SRM, Hadi AA, Abd Aziz KH. Exploring women’s perceptions and experiences of menopause among East Coast Malaysian women. Malaysian Family Physician: the Official Journal of the Academy of Family Physicians of Malaysia. 2021; 16: 84-92.
  19. Alwi SS, Brohi I, Awi I. Perception of menopause among women of Sarawak, Malaysia. BMC Women’s Health. 2021; 21: 77.
  20. Baber R. East is east and West is west: perspectives on the menopause in Asia and The West. Climacteric. 2014; 17: 23-28.
  21. Ayatollahi ST, Ghaem H, Ayatollahi SR. Menstrual-reproductive factors and age at natural menopause in Iran. International journal of gynaecology and obstetrics. 2003; 80: 311-313.
  22. Abdollahi AA, Qorbani M, Asayesh H, Rezapour A, Noroozi M, Mansourian M, et al. The menopausal age and associated factors in Gorgan, Iran. Medical journal of the Islamic Republic of Iran. 2013; 27: 50-56.
  23. Nohjah S, Latifi S, Mohamadjafari R. Age at natural menopause and its related factors in Ahvaz. Journal of Ahvaz University of Medical Sciences. 2006; 4: 221-216.
  24. Poustchi H, Eghtesad S, Kamangar F, Etemadi A, Keshtkar A-A, Hekmatdoost A, et al. Prospective epidemiological research studies in Iran (the PERSIAN Cohort Study): rationale, objectives, and design. American journal of epidemiology. 2018; 187: 647-655.
  25. Control CfD, Prevention. National Health and Nutrition Examination Survey (NHANES): Anthropometry procedures manual. CDC: 2007.
  26. Fallahzadeh H. Age at natural menopause in Yazd, Islamic Republic of Iran. Menopause. 2007; 14: 900-904.
  27. Zamaniyan M, Moosazadeh M, Peyvandi S, Jaefari K, Goudarzi R, Moradinazar M, et al. Age of natural menopause and related factors among the tabari cohort. Journal of menopausal medicine. 2020; 26: 18-23.
  28. Nouhjah S, Mohammad JR, Latifi S. The mean age of menopause and its determinant factors: a cross-sectional study in Ahwaz 2001-2002. 2005; 4: 216-222.
  29. Nahidi F, Karman N, Vallaei N, Fazli Z. Studying incidence of menopause and its effective factors in Tehran. Research in Medicine. 2010; 33: 258-265.
  30. Mohsenian S, Shabbidar S, Siassi F, Qorbani M, Khosravi S, Abshirini M, et al. Carbohydrate quality index: its relationship to menopausal symptoms in postmenopausal women. Maturitas. 2021; 150: 42-48.
  31. Mirinezhad MR, Khosroabadi N, Rahpeyma M, Khayami R, Hashemi SR, Ghazizadeh H, et al. Genetic determinants of premature menopause in a Mashhad population cohort. International journal of fertility & sterility. 2021; 15: 26-33.
  32. Shobeiri F, Nazari M. Age at menopause and its main predictors among Iranian women. International journal of fertility & sterility. 2014; 8: 267-272.
  33. Kowalcek I, Rotte D, Banz C, Diedrich K. Women’s attitude and perceptions towards menopause in different cultures: Cross-cultural and intra-cultural comparison of pre-menopausal and post-menopausal women in Germany and in Papua New Guinea. Maturitas. 2005; 51: 227-235.
  34. Muka T, Asllanaj E, Avazverdi N, Jaspers L, Stringa N, Milic J, et al. Age at natural menopause and risk of type 2 diabetes: a prospective cohort study. Diabetologia. 2017; 60: 1951-1960.
  35. Reynolds RF, Obermeyer CM. Age at natural menopause in Spain and the United States: results from the DAMES project. American Journal of Human Biology: The Official Journal of the Human Biology Association. 2005; 17: 331-340.
  36. Pathak R, Parashar P. Age at menopause and associated bio-social factors of health in Punjabi women. The open anthropology journal. 2010; 3: 172- 180.
  37. Zhang L, Ruan X, Cui Y, Gu M, Mueck AO. Menopausal symptoms among Chinese peri-and postmenopausal women: a large prospective single-center cohort study. Gynecological Endocrinology. 2021; 37: 185-189.
  38. Fenton A, Panay N. What influences the age of menopause? : Taylor & Francis; 2015;8: 767-768.
  39. Kaczmarek M. The timing of natural menopause in Poland and associated factors. Maturitas. 2007; 57: 139-153.
  40. Hardy R, Kuh D, Wadsworth M. Smoking, body mass index, socioeconomic status and the menopausal transition in a British national cohort. International journal of epidemiology. 2000; 29: 845-851.
  41. Franceschi S, La Vecchia C, Booth M, Tzonou A, Negri E, Parazzini F, et al. Pooled analysis of 3 European case-control studies of ovarian cancer: II. Age at menarche and at menopause. International journal of cancer. 1991; 49: 57-60.
  42. Morabia A, Costanza MC, Neoplasia WHOCSo, Contraceptives S. International variability in ages at menarche, first livebirth, and menopause. American Journal of Epidemiology. 1998; 148: 1195-1205.

Citation: Roozbeh N, Masoudi M, Moannaie M, Nejatizadeh A and Kutenaee MA. A Prospective Study of Factors Affecting Age at Menopause among the Bandar-E-Kong Cohort. Austin J Womens Health. 2021; 8(3): 1058.