Obesity is yet a neglected public health concern. It is a chronic disease, with multifactorial genesis, requiring concerted efforts, posing as an important risk factor for the development and deterioration of another diseases [1]. Worldwide obesity has nearly tripled since 1975. In 2016, more than 1.9 billion adults were overweight. Of these, over 650 million were obese. Musculoskeletal (MSK) pain is one of several disorders associated with obesity [1].

Back pain, including thoracic spinal pain, is a common, potentially disabling, routine presenting complaint to general practitioners [2]. When it comes to women and back pain, most people think about the standard reasons for discomfort: injury or accidents, physical work, active sports lifestyles, and similar factors that often cause back pain in both men and women. But there is a factor that is specific to women, which is the breast size.

Women with large breasts usually have a number of complaints relating to the skeletal system, and complaints such as neck strain, headache, aching shoulders, and heavy anterior chest. Macromastia can cause various clinical symptoms, such as low back and shoulder pain as well as sacroiliac disorders [3].

Macromastia is the state of having disproportionately large breasts. Some macromastic women report breast pain and other symptoms, and the intuitively logical assumption is that breast size is the key influence on clinical presentation [4]. Clinical symptoms attributed to macromastia include neck, thoracic spine and shoulder pain, breast pain, headaches, grooving and associated pain caused by bra straps, intertrigo (inflammation of skinfolds), and ulnar nerve paresthesia [5].

Breast size and mass changes across the life-span suggesting that macromastic symptoms may occur episodically during particular stages of life. Although these symptoms are widely reported, the relationship between breast size and symptoms is somewhat unclear [6,7]. Breast mass and breast density appear to be important variables. Most outcome studies of reduction mammaplasties support the view that larger breasts equate to greater health burden demonstrate this relationship through symptom improvement post- surgery, but a recent review of 59 women who underwent reductions involving the removal of less than 1000g of breast tissue showed that small reductions in breast mass may result in statistically significant improvements in macromastic symptoms [8][4]. They also suggested that large or heavy breasts may also lead to continuous tension on the middle and lower fibers of the trapezius muscle and associated muscle groups [9].

Studies have shown that increased obesity levels were associated with compromised kyphosis and loading of the thoracic spine, as well as increased symptoms of upper torso musculoskeletal pain few studies have found that BMI is related to development of thoracic pain in women with large breast [10]. Moreover, majority of Africa women experience pain but few may attribute it to hypertrophic breast. Therefore, this study will categorize the women bust based on age, the BMI and also determine the association between the bust size, BMI and occurrence of thoracic pain [11].

167 women were recruited for this cross-sectional study based on their bra size level. Ethical approval and informed consent were obtained. Participants completed a questionnaire about age, pregnancy, breastfeeding, bust size, and thoracic pain. Their bust size was measured using standardized guidelines if they couldn't provide their own score.  Bust size was measured using under-bust and over-bust circumferences according to Triumph guidelines. A conversion chart converted measured size to a continuous score. Body Mass Index (BMI) was calculated using weight and height measured with a weighing scale and height meter. Participants were categorized as underweight, normal weight, overweight, or obese based on standard BMI ranges.  Thoracic pain intensity was Assessed using a 10 cm Visual Analog Scale (VAS), where 0 = no pain and 10 = worst imaginable pain. Participants marked their pain level on the line. Data were analyzed using descriptive and inferential statistics in SPSS version 23. Significance was set at p<0.05.

Demographic and General Characteristics of the Participants

The majority of the young women were between the age range 25-30 years, obese, had medium bust size and their level of thoracic pain was low in this study (Table 1, Figure 1,2,3).

Association between Bust size and Level of Thoracic Pain of the Participants

The result revealed that there was a significant association between Bust size and the Thoracic pain level of the participants (x² = 20.448, p = 0.000). (Table 2).

Association between Bust size and Body Mass Index of the Participants

 The result revealed that there was significant Association between the Bust size and Body Mass Index of the participants (x² = 31.686, p = 0.000). (Table 3).

Figure 1: Bar chart showing women bust size category.

Figure 2: A pie chart showing the percentage of body mass index.

Figure 3:  Bar chart showing the level of thoracic pain.

Appendix 1: The Triumph-International chart.

Table 1: Demographic and General Characteristics of the Participants.

Table 2:  Association between Bust Size and Thoracic Pain Level of the Participants.

Table 3: Association between Bust Size and Body Mass Index of the Population.

This study examined the association between Bust Size and Body Mass Index with the prevalence of thoracic spine pain among young adult women. In this study, it was observed that Bust Size had a significant association with Body Mass Index. This result is supported by a study done.

The results of this study found that the anthropometric variables measured were significantly greater in larger-breasted women, rejecting hypothesis two and this supports previous research, which hypothesizes that differences in breast size and mass are attributed to variations in adiposity. In agreement with previous research [12].

 This study highlights the effects of Body Mass Index on breast size as well as thoracic spine pain reported by a cohort of young adult women of primary concern was the finding that the women classified as Obese reported significantly more thoracic spine pain. It was also observed that there was significant association between the Bust Size and Thoracic spine pain this study is comparable [11]. Radiological images of the spine in women with large breasts (size of the bra D +) showed a much higher thoracic kyphosis, compared with women with small breast [12].

Researches proved that the size of the breasts is associated with pain of the musculoskeletal system. The above results were explained, according to whom the torso muscles showed positive, moderately strong correlations with the size of the breast while standing and some movements of the trunk. The size of the breast is associated with a changed posture, which in the long-term perspective, may cause pathological changes leading to pain. Changes in the posture of women with large sized breasts were noted by Barbosa et al., who examined women with breast hypertrophy compared to healthy women further study is required to verify this notion.

Although greater breast size associated with obesity is likely to be a strong contributor to the increased thoracic pain reported by the participants in the present study classified as Obese, it was not the only contributing factor, Wearing incorrectly sized bras has also been reported in young women with thoracic pain [13].This study has identified an association between thoracic pain, body mass index and bust size in young women [14-19]. It is acknowledged that additional possible correlates exist and in this study it was not possible to account for all of these use of correctly fitted bra, personality disorders, physical activity levels, emotion and in some instances, occupational stresses, are factors that were not measured and may have confounded in this study [20-23].

The findings suggest a positive association between bust size and both BMI and the occurrence of thoracic pain in young adult women.

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