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

Roozbeh N; Masoudi M; Moannaie M; Nejatizadeh A; Kutenaee MA

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.

Download PDF

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.

Home

Journal Scope

Editorial Board

Instruction for Authors

Submit Your Article

Variable		Total (n=894)			premature menopause age (n=79)			early menopause age (n=116)			normal menopause age (n=699)
Variable		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
Infertility	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

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

Abstract

Introduction

Materials and Methods

Patients and study design

Results

Discussion

References