TypeError: Not supported between instances of 'function' and 'int'

[palladium]

Hi all, I am new to programming and am trying (learning) to build a calculator to calculate the risk of heart diseases based on a few variables. Part of the calculation requires recognition of certain high risk criteria and this is where I am at the moment. The code is split into two files, variables.py (the variables module) and framingham.py:

Variables.py:

def age():
  a = eval(input("Please enter age in years: "))
  if a < 35:
    return 35
  else:
    return a

def systolic_blood_pressure():
  b = eval(input("Please enter SBP: "))

  if b < 75:
    return 75

  else:
    return b

def cholesterol_ratio(total_cholesterol, HDL_cholesterol):
    ratio = total_cholesterol/HDL_cholesterol

    return ratio

def smoker():
  a = eval(input("Are you a smoker? 0 = no, 1 = yes " ))
  return a

def diabetes():
  a = eval(input("Are you a diabetic? 0 = no 1 = yes " ))
  return a

def LVH():
  a = eval(input("Does the ECG show LVH? 0 = no 1 = yes " ))
  return a

total_cholesterol = eval(input("Please enter total cholesterol. "))
HDL_cholesterol = eval(input("Please enter HDL cholesterol. "))

framingham.py (incomplete):

import variables
from sys import exit

#define and return if high risk criteria present
class highrisk(object):

  def __init__(self, age, diabetes, systolic_blood_pressure, total_cholesterol):
    self.age = variables.age
    self.diabetes = variables.diabetes
    self.systolic_blood_pressure = variables.systolic_blood_pressure
    self.total_cholesterol = variables.total_cholesterol

    if total_cholesterol >= 7.5:
        print("You are at high risk of developing heart disease. ")

    elif systolic_blood_pressure >= 180:
        print("You are at high risk of developing heart disease. ")

    elif age >= 60 and diabetes == 1:
        print("You are at high risk of developing heart disease. ")

    else:
        pass #no output needed if none of the criteria are met

#actual risk calculator
class risk_calculator_male():
    pass

class risk_calculator_female():
    pass

highrisk(variables.age, variables.diabetes, variables.systolic_blood_pressure, variables.total_cholesterol)

(The pass in the last 2 classes are temporary as I haven't finished researching/planning the formula yet)
When I run framingham.py in the CLI, I get the following traceback:

Error:
PS D:\python\framingham> python framingham.py
Please enter total cholesterol. 5
Please enter HDL cholesterol. 1
Traceback (most recent call last):
  File "framingham.py", line 32, in <module>
    highrisk(variables.age, variables.diabetes, variables.systolic_blood_pressure, variables.total_cholesterol)
  File "framingham.py", line 16, in __init__
    elif systolic_blood_pressure >= 180:
TypeError: '>=' not supported between instances of 'function' and 'int'

I thought the eval() function already converts the string to int/float?

Some help would be much appreciated. Thanks