SSC 2011 Case Study 2

Determinants of the Presence and Volume of Brown Fat in Human

Content last modified 2011-01-22
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Table of Contents

Acknowledgements

Thanks to the Molecular Imaging Center at The University of Sherbrooke for providing the data.

Please address queries to Lajmi Lakhal-Chaieb at the Department of Mathematics and Statistics at Université Laval.

Objective

The objective of this analysis is to identify the factors determining the existence and the volume of brown fat in Humans.

Background

It is well known that brown fat allows some small animals to live in a cold environment. In humans, until recently it was believed that this fat was present only in newborns. However, recent technological advances have detected its presence in adults as well. This fat needs to be activated by a low ambient temperature to be detected by scanning as the cold exposure increases the prevalence, which varies considerably from a study to another. However, the importance of the factors determining the existence and the volume of the brown fat in adults are still to be investigated. The main purpose of the study is to examine the relationship between a number of factors and the presence and the volume of brown fat in a large cohort of cancer patients.

Questions

The students can consider the following questions:

  1. Investigate the relationship between each of the covariates and the presence and volume of brown fat separately.
  2. Build models to estimate the probability of having brown fat and predict its volume.
  3. Actually, there are four different patterns of brown fat: Cervical, Paravertebral, Mediastinal and Perirenal. Perform the previous analysis by considering multivariate outcomes.

Data

A data set with records on 4842 cancer patients is available (CSV, XLS) to perform the analysis. This data set contains all explanatory and response variables. These are:

  • Sex: sex of the patient (Female=1, Male=2).
  • Diabetes: (No=0, Yes=1).
  • Age: Age of the patient in years.
  • Day: Day of the year.
  • Month: Month of the exam.
  • Ext_Temp: External Temperature.
  • 2D_Temp: Average temperature of last 2 days.
  • 3D_Temp: Average temperature of last 3 days.
  • 7D_Temp: Average temperature of last 7 days.
  • 1M_Temp: Average temperature of last month.
  • Season: Spring=1, Summer=2, Automn=3, Winter=4.
  • Duration_Sunshine: Sunshine duration.
  • Weight: in Kgs
  • Size: in cms.
  • BMI: Body Mass index.
  • Glycemia.
  • Lean Body Weight.
  • Cancer_Status: (No=0, Yes=1).
  • Cancer_Type: (No=0, lung=1, digestive=2, Oto-Rhino-Laryngology=3, breast=4, gynaecological (female)=5, genital (male)=6, urothelial=7, kidney=8, brain=9, skin=10, thyroid=11, prostate=12, non-Hodgkin lymphoma=13, Hodgkin=14, Kaposi=15, Myeloma=16, Leukemia=17, other=18).
  • TSH
  • BrownFat: (No=0, Yes=1).
  • Total_Vol: Total volume of Brown Fat.
  • Cervical_volume: Volume of cervival.
  • Paravertebral_vol: Volume of Paravertebral.
  • Mediastinal_vol: Volume of mediastinal.
  • Perirenal_vol: Volume of perirenal.

 

Frequently Asked Questions

References