Table 2.

Summary of Two-Wave Citations (n = 3) and Mixed-Wave Citations (n = 7) Partially Meeting Inclusion Criteria for the Systematic Review: Sample and Study Characteristics, and Main Findings

First author, year		Study	Sample characteristics	Geographic region	No. of participants	Waves of data collection	% Male	Baseline age range (years)	Pulmonary measures	Statistical method
Emery, 1998		Swedish Adoption/ Twin Study of Aging (SATSA)	Population-Twin	Sweden	444	2	40	40–84	FEV1	Hierarchical multiple regression
Cognitive battery	(Latent) Domain:	Processing speed (Fluid intelligence)	Spatial ability (Fluid intelligence)	Memory (Fluid intelligence)	Verbal ability (Crystallized intelligence)
	Tests:	Digit symbol	Block design	Digit span	Information
Main result	Baseline FEV1 predicted performance in processing speed and spatial ability measures at baseline and 6-year follow-up, but did not predict change in any of the cognitive outcomes.
Richards, 2005		Medical Research Council National Survey of Health and Development (MRC NSHD)	Population	United Kingdom	3,035	2	49.8	43	FEV1	Conditional change score models
Cognitive battery	(Latent) Domain:	Processing speed/ concentration	Memory	Verbal ability
	Tests:	Timed Peg Placement Test	Word List Recall	National Adult Reading Test
		Letter Search
Main result	Baseline FEV1 was associated with processing speed at baseline and slower decline in processing speed over time. No association between FEV1 and memory or verbal ability.
Starr, 2007		1947 Scottish Mental Survey	Population	Scotland	298	2	47	64	FEV1 PEF FVC	Linear mixed effects models
Cognitive battery	(Latent) Domain:	Non-verbal reasoning/ spatial ability	Verbal memory	Executive function	Processing speed
	Test(s):	Raven’s Progressive Matrices Block design	Auditory Verbal Learning test	Use of common objects test	Digit symbol
Main result	Higher PEF was associated with better performance on all cognitive tests except Auditory Verbal Learning at age 64 and 66 years.
Aiken-Morgan, 2018		Baltimore Study of Black Aging - Patterns of Cognitive Aging	Population	United States	407	Pulmonary: 1 cognitive: 2	—	48–95	PEF	Multivariate and Univariate Analysis of Variance
Cognitive battery	(Latent) Domain:	Inductive reasoning	Declarative memory	Processing speed	Working memory		Verbal ability		Executive functioning
	Tests:	Letter Series Test	Hopkins Verbal Learning Task	Number Comparison Test	Alpha Span		Verbal Ability Test		Clock Drawing Test
		Shipley Institute of Living Scale Abstraction Test	Rey Auditory Verbal Learning Task	Identical Pictures Test Digit Symbol	Operation Span Digit Span Backwards		Shipley Institute of Living Verbal Meaning Test
Main result	Better lung function at baseline was significantly associated with cognitive stability over 3 years.
Infurna, 2013		Health and Retirement Study (HRS)	Population	United States	4,177	Pulmonary: 1 cognitive: 2	41	66.75*	FEV1	Latent change score models
Cognitive battery	(Latent) Domain:	Episodic memory
	Tests:	Word List Immediate Recall
		Word List Delayed Recall
Main result	FEV1 at baseline was significantly associated with 4-year change in memory; better pulmonary function predicted less memory decline.
Koster, 2005		Health, Aging and Body Composition (Health ABC) study	Population	United States	2,574	Pulmonary: 1 cognitive: 2	—	70 –79	FEV1 FVC	Chi-square tests
Cognitive battery	(Latent) Domain:	General cognitive status
	Tests:	Modified MMSE (3MS)
Main result	Low FEV1 at baseline was significantly associated with 4 year decline in cognitive function.
Pathan, 2011		Atherosclerosis Risk in Communities Study	Population	United States	10,975	Pulmonary: 1 cognitive: 2–3	—	45–64	FEV1 FVC	Multivariable linear regression
Cognitive battery	(Latent) Domain:	Verbal memory	Executive function/ processing speed	Processing speed
	Tests:	Delayed Word Recall	Digit Symbol	Word Fluency Test
Main result	Reduced FEV1 or FVC at baseline was significantly associated with worse cognitive function at baseline, and higher risk of dementia at follow-up. No association was observed between reduced FEV1 or FVC and cognitive decline.
Swan, 1992		National Heart, Lung, and Blood Institute (Bethesda, MD) Twin Study	Population	United States	792	Pulmonary: 1 cognitive: 2	–	MZ–57.1* DZ 56.3*	FEV1 FVC	Heritability analysis, t and F tests
Cognitive battery	(Latent) Domain:	Processing speed
	Tests:	Digit symbol
Main result	Cognitive decline in twin pairs measured by the digit symbol substitution test had significantly poorer lung function than twin pairs with no cognitive decline.
Vidal, 2013		AGES-Reykjavik study (2002–2006) Cohort	Population	Iceland	5764	Pulmonary: 2–3 cognitive: 1	33	52*	FEV1/height2	ANOVA and logistic regression
Cognitive battery	(Latent) Domain:	Memory	Processing speed	Executive function	General cognitive status
	Tests:	California Verbal Learning Test	Figure Comparison Test	CANTAB Spatial Working Memory Test	MMSE
			Digit symbol	Digit Span Backwards
			Stroop	Stroop
Main result	Lower FEV1/height2 at mid-life were more likely to have lower cognitive test scores or to develop MCI or dementia 23 years later.
Whitfield, 1997		MacArthur Research Network on Successful Aging Community Study	Population	United States	224	Pulmonary: 1 cognitive: 2	40	70 to 79	PEF	Linear regression analyses and logistic regression
Cognitive battery	(Latent) Domain:	Memory	Language	Conceptualization	Visuospatial ability
	Tests:	Delayed Verbal Memory	Boston Naming Test	Similarities	Delayed Recognition Span
					Figure Copy
Main result	Baseline PEF was significantly associated with cognitive performance. PEF significantly predicted cognitive decline between intervals.

Note: FEV₁ = forced expiratory flow (in 1 s); PEF = peak expiratory flow; MMSE = Mini-Mental Status Examination; MZ = Monozygotic twin pairs; DZ = Dizygotic twin pairs; *Age displayed as mean.