An investigation into the association between breast size, muscle sensitivity and upper back pain in pre-menopausal women in Durban, KwaZulu-Natal

Abstract

Background: Previous studies have examined the relationship of breast size on the upper back pain and posture however, the majority of these studies focused on postural alternations and post-menopausal women alone, leaving limited literature regarding the effect of breast size on the upper back musculature. The muscular sensitivity of the upper back region in relation to breast size has been surveyed in Australia not in South Africa it requires further investigation. The difference in cultural and ethnicity differences among Australians and South Africans negate the direct extrapolation of findings. Understanding the effect of breast size on the upper back pain and its surrounding musculature provides more insight into how healthcare practitioners consider treatment of women presenting with upper back pain to improve the treatment outcomes and patient satisfaction. Aim: The aim of this study has been to determine if there is an association between breast size, muscle sensitivity and self-reported upper back pain in pre-menopausal women in Durban, KwaZulu-Natal. Methodology: This was a quantitative, case-controlled, observational study design. A pressure algometer was used to measure the pain pressure threshold of 12 anatomical sites. A sample of 52 participants were recruited and divided into one of two groups: one with upper back pain and one without upper back pain. Within the groups, comparisons were made using the test. A two-sided p-value of <0.05 as alpha was considered as statically two-sample t-significant. Results: Breast size has an effect of the muscle sensitivity of the upper back anatomical sites. After self-reporting of pain, breast size A and B was most commonly found in the non- pain group where breast size D or higher was found to be most in the pain group (p= 0.054) when comparing differences between the pain and non-pain groups of five anatomical locations. Using A or B cup size as the reference group, size C has 2.2 times higher odds of being in the pain group which was not statistically significant (p=0.220) and cup sizes D or higher has almost 5 times higher odds of being in the pain group (p=0.054).

Conclusion: The results of this study show that, overall, an association exists between breast size,muscle sensitivity and self-reported upper back pain in pre-menopausal women. This was significantly noted as the cup size increased, muscle sensitivty increased,indicating a lower kPa value in T8,T10, levator scapulae, upper trapezius and middle trapezius. This stands in contrast to previous studies who noted that only the middle trapezius had the greatest variability between groups with different pain levels amongst post menopausal women, with no control group to compare findings. As a result, the null hypothesis was rejected.