Please read the following abstract by Bigman et al.2022 and answer the following questions.

Bigman G, Adebamowo SN, Yawe KT, Yilkudi M, Olaomi O, Badejo O, Famooto A, Ezeome E, Salu IK, Miner E, Anosike I, Achusi B, Adebamowo C. Leisure-time physical activity is associated with reduced risks of breast cancer and triple negative breast cancer in Nigerian women. Cancer Epidemiol. 2022 Aug;79:102195.

Background: Leisure-time physical activity(LTPA) is associated with a reduced risk of breast cancer, but this has less been investigated by cancer subtypes in Africans living in Sub-Saharan Africa(SSA). We examined the associations between LTPA and breast cancer including its subtypes in Nigerian women and explored the effect modification of body size on such associations.

Methods: The sample included 508 newly diagnosed primary invasive breast cancer cases and 892 controls from the Nigerian Integrative Epidemiology of Breast Cancer(NIBBLE) Study. Immunohistochemical(IHC) analysis was available for 294 cases. Total metabolic equivalents(METs) per hour/week of LTPA were calculated and divided by quartiles(Q1 <3.75, Q2:3.75-6.69, Q3:6.70-14.74, Q4:14.75 ). We applied logistic regressions to estimate the adjusted Odds Ratios(ORs) between LTPA and breast cancer and by its molecular subtypes and whether age-adjusted associations are modified by BMI.

Results: The mean age(MeanSD) of cases vs. controls(45.5 11.1vs.40.1 9.0) was higher, and the mean total METs hour/week was higher in controls vs. cases(11.9 14.9vs.8.3 11.1,p-value<0.001). Overall, 43.2%(N = 127/294) were classified as HRP, and 41.8%(N = 123/294) as TNBC. Women in the higher LTPA quartiles(Q3-Q4) vs. Q1 had lower odds of having breast cancer(ORQ4vs.Q1=0.51,95%CI:0.35-0.74) and TNBC(ORQ4vs.Q1=0.51, 95%CI:0.27-0.96), but not HRP(ORQ4vs.Q1=0.61,95%CI:0.34-1.09) after adjusting for age, age at first menarche, body size, breastfeeding, menopausal, parity, contraceptives, demographics, alcohol, smoking, and physical activity at home and work. Lastly, LTPA and its age-adjusted association with breast cancer was more pronounced in women with BMI< 30 vs. BMI 30 + .

Conclusions: LTPA may reduce the risk of breast cancer, especially TNBC, which is the more aggressive and prevalent molecular subtype of breast cancer in SSA.

A) What is the unit of observation? Please select one.

a. Individual

b. Group

c. Both

B) Are the same individuals measured at multiple points in time?

a. Yes

b. No

C) Which type of study design best describes Bigman et al. 2022? Please select one.

a. Cross-sectional

b. Repeated cross-sectional

c. Case Series

d. Case control

e. Ecologic cross-sectional

f. Ecologic (repeated)

g. Randomized control trial

h. Intervention, (not randomized)

i. Cohort