Clinical trial NCT01034098: Ventilatory Constraint, Breathing Pattern and Ventilatory Responses in Obese Postmenopausal Women
Official title: Ventilatory Constraint, Breathing Pattern and Ventilatory Responses in Obese Postmenopausal Women
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Obesity
Postmenopausal Women
Keywords: Obesity
Postmenopausal women
Mechanical ventilatory constraints
Dynamic lung volume
Expiratory flow limitation
Lead sponsor: National Taiwan University Hospital
Sponsor class: OTHER
First posted: 2009-12-17
Enrollment: 50
Sex: FEMALE
Minimum age (years): 50
Maximum age (years): 69
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: CROSS_SECTIONAL
Sampling method: PROBABILITY_SAMPLE
Study population: Postmenopausal women (for at least 1 year) who aged below 69 y/o without hormone replacement therapy

Brief summary: The purpose of this study was to examine the dynamic lung volumes in obese post-menopausal women (without hormone replacement therapy) during exercise and their correlations with dyspnea.

Detailed description: Obesity-related changes in lung volumes have shown to affect breathing mechanisms. During exercise, altered breathing mechanisms increase potential for expiratory flow limitation and compromise exercise capacity. Estrogen and progesterone are potent respiratory stimulants, and their effects in the physiologic regulation of breathing are down-regulated after menopause. Therefore, we theorized that the combined obesity and reduced sex hormone levels after menopause work as a double jeopardy to cause mechanical ventilatory constraint which aggravates dyspnea sensation during exercise, and thus a reduction in exercise capacity. The purpose of this study was to exam the dynamic lung volumes in obese post-menopausal women (without hormone replacement therapy) during exercise and their correlations with dyspnea.

From doctoral referral and advertisement, 24 obese (BMI ≧ 27 kg/m2) and 26 lean post-menopausal women were recruited for the study. Pulmonary function and body composition were measured at rest. A maximal flow volume loop (MFVL) was obtained at baseline. All subjects then performed an incremental exercise test on a cycle ergometer with workload increasing 25 watts every 3 min. During exercise, at each workload, the tidal exercise FV loops were obtained and an inspiratory capacity (IC) maneuver was conducted to assess changes in end-expiratory lung volume (EELV) and end inspiratory lung volume (EILV). Dyspnea and leg fatigue were assessed using the Borg scale. Analysis of variance with repeated measurements was used to test the significance of the mean differences between the two groups during exercise. Linear regression analysis was used to determine whether changes in dynamic lung volumes during exercise were related to changes in Borg scores. Statistical significance was established at p\<0.05.

Eligibility criteria: Inclusion Criteria:

* Postmenopausal women (for at least 1 year)
* Age below 69 y/o
* Not receiving hormone replacement therapy

Exclusion Criteria:

* Cardiopulmonary disease
* Musculoskeletal disease affecting results of maximal exercise test

Primary outcomes:
measure: Dynamic lung volume: end-expiratory lung volume (EELV), end-inspiratory lung volume (EILV)
timeFrame: At least 1 year post-menopause
Secondary outcomes:
measure: Pulmonary function
timeFrame: At least 1 year post-menopause
measure: Breathing pattern
timeFrame: At least 1 year post-menopause
measure: Ventilatory response
timeFrame: At least 1 year post-menopause
measure: Visual analog scale (VAS) for dyspnea and leg fatigue
timeFrame: At least 1 year post-menopause
Other outcomes:
Locations:
city: Taipei
country: Taiwan
facility: School and Graduate Institute of Physical Therapy, National Taiwan University
Study officials:
affiliation: School and Graduate Institute of Physical Therapy, National Taiwan University
name: Li-Ying Wang, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References: