Effects of Breast Size on Lung Function

Aim: A few previous studies reported contradictory results about the effects of reduction mammaplasty on pulmonary function tests. This study was conducted to evaluate the effects of breast size on pulmonary functions in volunteer healthy adult women that, to the best of our knowledge, was not reported before. Method: Ages, body mass indices, and underband and overbust measurements for breast sizes of 100 adult female volunteers without any known lung disease subjects were recorded. Differences between the overbust and underband measurements gave the cup sizes. Four groups were formed according to the cup sizes as: <6.5 cm (cup size A), 6.5 to 13 cm (cup size B), 13-19.5 cm (cup size C), and >19.5 cm (cup size D). Pulmonary function tests were performed to each subject Result: Pulmonary function tests did not show significant difference between groups. Difference of body mass index was significant between groups. Age, body mass index, and cup size were found in positive correlation with each other. Body mass index was negatively correlated with forced expiratory volume in 1 second, forced vital capacity, and forced expiratory volume in 1 second / forced vital capacity. Conclusion: Breast size had no correlation with lung function in healthy volunteer women. Body mass index seems as the main factor affecting the lung function.


INTRODUCTION
Surgical reduction of large breasts has been increasingly performed not only for aesthetic complaints, but also physical and psychological health problems including breast pain, back pain, neck pain, shoulder pain and grooving, and intertriginous rashes.Respiratory restriction has also been suggested to be relieved after the bilateral breast reduction.A few previous studies on this topic were either a subjective analysis of patient comments or comparison of pulmonary function tests (PFTs) before and after reduction surgery.1-5Besides the contradictory results of those reports, both "learning effect" of repeated PFTs and weight of removed specimen that diminishes the original body mass index (BMI) postoperatively might have also some effects on results.
A few previous studies regarding the effect of reduction mammaplasty on pulmonary function tests reported improvements in PFTs after reduction mammaplasty, in the other hand some others reported contradictory results (1)(2)(3)(4)(5).Therefore, BMI may be the key linking whether a reduction mammmaplasty may affect PFTs, so it is worthwhile to investigate the relationship between bra cup size, BMI and PFTs in normal adult females.
To contribute the solution of this conflict, we planned to evaluate the effects of breast size on pulmonary functions in a group of volunteer adult women.To the best of our knowledge, the effect of breast size on pulmonary function has not been shown in normal women population previously.

Study design
One hundred female volunteers without any known lung disease and recent or ongoing respiratory infection were enrolled into the study.Volunteers were all nonsmoker, older than 17 years old.None of them was pregnant, lactating, and had no breast or anterior chest wall operation.All the volunteers gave an informed consent, and ethical approval was obtained from the institutional board.Ages, weights, and underband and overbust measurements for breast sizes of subjects were recorded.

Methods
BMIs were calculated using the formula: weight/height2 (kg/m2).Obesity is defined as a BMI >30 kg/m2, and a BMI > 40 kg/m2 corresponds to morbid obesity.6,7Cup sizes of breasts were calculated using a previously described method: differences between the overbust and underband measurements gave the cup sizes of participants.8Four groups were formed according to the cup sizes as: <6.5 cm (cup size A), 6.5 to 13 cm (cup size B), 13 to 19.5 cm (cup size C), and >19.5 cm (cup size D).
PFTs were conducted using spirometry instrument (Zan 200, PROV air II, Germany) in accordance with the criteria of American Thoracic Society.9Firstly, the cases were told how the test was going to be carried out and the maneuver to be used was shown by conducting the test once more, when necessary.The cases put on nose clips in sitting position and were made to perform forced vital capacity maneuver.A maximum of five consecutive measurements were made and the results were recorded after choosing the best value.Tests carried

Statistical analysis
Kolmogorov-Smirnov test confirmed a normal distribution pattern.To analyze the effect of breast size on lung function tests, Oneway ANOVA test was established and a p value < 0.05 was assumed as significant.Spearman correlation analysis was used to evaluate the relation between PFTs and BMI, and PFTs and breast size.

RESULTS
The mean age was 34.7±9.6 years (range, 18-53 years).The age distribution was homogenous between groups A, B, C, and D. The BMI ranged between 18.1 kg/m2 and 43.1 kg/m2 (mean, 28.3±6.2kg/m2).There were 22 women in group A, 34 women in group B, 30 women in group C, and 14 women in group D.
Forty-one volunteers had simple obesity (BMI > 30 kg/ m2) and six volunteers had morbid obesity (BMI > 40 kg/ m2) in our study.Distribution of age, BMI, and PFTs between groups is presented in table 1.No significant difference of PFTs was found between groups.Difference of BMI was significant between cup size groups (table 1).In the correlation analysis, no correlation was found between groups and lung function parameters.Age, BMI, This also correlated positively with BMI; the more obese the patient was, the more the improvement there was in pulmonary function.According to those authors, the improvement in maximum voluntary ventilation implies that the reduction in breast mass improved overall chest wall compliance, thereby resulting in an improvement of dyspnea.The mean resection weight was 2220 g in that study.More recently, Iwuagwu et al.5 made a randomized comparative analysis and showed no significant difference in PFTs.However, they demonstrated a positive correlation between specimen weight resected (mean 1382 g) and FVC1/vital capacity (%); FEV/FVC; peak expiratory flow rate, and forced vital capacity.In contrary to previous reports, they found no correlation between BMI and PFTs possibly because that was not the main subject of their study.
All of the patients in above mentioned studies (excluding the Conway and Smith who did not study PFTs) had PFTs within the normal limits before and after surgery, but the clinical significance of the improvements in test values beyond normal seems debatable.In addition, PFTs may be affected by patient weight and can be changed by learning (repeat tests).Both learning effect in repeated PFTs and weight of removed specimen that diminishes the original body mass index postoperatively have potential effects on the results of those studies.Perhaps the improvements in PFTs are related to BMI and if a female is morbidly obese and a reduction mammmaplasty leads to a decrease in bodyweight and BMI, than PFTs may improve also.
In the present study, BMI was found in negative correlation with FEV1, FVC, FEV1/FVC, FEF50, and FEF25%.However, we found no correlation of these parameters with breast size.Women who have large breasts also have high body mass index as demonstrated in our study (table 1).In association with obesity, macromastia may lead to a relative restriction in chest wall compliance; therefore, reduction of breast size is expected to enhance chest wall compliance and lead to improved ventilation.Breast size contributes BMI, but it is not the only and most important constituent of it A further study with a larger volunteer group including enough subjects from various body types will be beneficial.
Breast size had no correlation with lung function in the present study that was performed with 100 healthy vol-unteer women aged between 18 and 53.Also, in previous studies about the effect of reduction mammaplasty, observed women had no respiratory illnesses.2-5We think that our results may contribute to unravel the debate appeared by controversial results of previous reports.However, this may not the case for women with both respiratory disease and large breasts.Reduction mammaplasty may improve lung function associated with enhanced chest wall compliance in patients with respiratory disorders like asthmatics.This may be a subject of further studies.
Main subject of our present study was the effect of breast size on lung function but not the effect of reduction mammaplasty.However, both methods focus on the same question: is lung function changed with large breasts?If so, an improvement of lung function would be expected with breast reduction.Regarding our findings and contradictory results in previous literature, as a matter of fact, breast reduction does not seem as a reliable way of improvement for pulmonary function in healthy women.Operative goals should be kept patientcentered and improvement of aesthetics and capacity of activity, pain relief, and ensuring self-confidence seem still the main objectives of reduction mammaplasty.

Table 1 .
Distribution of age, BMI, and pulmonary function tests between groups.