\begin{tabular}{@{\extracolsep{5pt}} cccccccc}
  \\[-1.8ex]\hline 
  \hline \\[-1.8ex] 
ID & Demo & Gender & ABO Type  & BMI (\si{\kg\per\m\squared}) & HLA-A2 Present \\
  \hline \\[-1.8ex]
4   & AA   & M & NA   & 21.7 & FALSE \\
24  & C    & M & NA   & 23.9 & FALSE \\
29  & AA   & M & NA   & 20.9 & TRUE  \\
30  & AA   & M & NA   & 20.9 & TRUE  \\
309 & C/PI & F & APOS & 24.9 & FALSE \\
338 & C    & M & OPOS & 23.4 & TRUE  \\
358 & C    & F & OPOS & 37.1 & TRUE  \\
397 & C    & M & OPOS & 31.2 & FALSE \\
512 & C    & M & OPOS & 26.5 & FALSE \\
592 & H    & M & APOS & 31.8 & FALSE \\
  \hline \\[-1.8ex]
\end{tabular} 